I have before me an application to deal with what are said to be late experiments. The context in which this arises is as follows.

The rules applicable to patent actions, which are in Practice Direction 63, part 7.1, provide as follows:

The rule uses the word "must". It is mandatory.

Two cases have a bearing on the issue that arises before me. The first is Consafe v Emtunga [1999] RPC 154. In that case Pumfrey J was dealing with the question of what an experiment was. He held that a finite element analysis was an experiment. At paragraph 16 of his judgment on page 62 he noted that because the finite element analysis required an exercise in judgment, it was an experiment and notice should have been given to enable the party on the other side to assess the analysis and either criticise it or accept it. He also cited the judgment of Laddie J in Electrolux v Black & Decker [1996] FSR 595. The extract cited by Pumfrey J includes a well known passage by Laddie J which is at line 30 of the report of Consafe. The predecessor rule in the Rules of the Supreme Court is in the same terms and is mandatory, not permissive. Such experiments will not be admissible in the absence of a notice unless in the special circumstances the court exercises its discretion to allow them.

The other relevant case is Monsanto v Cargill [2008] FSR 7, 153. Here Pumfrey J excluded certain experiments. Having found in paragraph 103 that procedurally there was prejudice to the party who was faced with the experiments which were not in accordance with the rules in the circumstances arising before him, in paragraphs 104 and 105 of his judgment he said this:

An extract from the decision of Kitchin J in Novartis v Johnson & Johnson on 10th July 2009 was also cited before me. Since in that case the question of whether transmission electron micrographs were or were not experiments did not arise because a notice had been served, it does not seem to me that that judgment is of assistance on this point.

The order for directions contained a regime dealing with experiments. It was an order of Arnold J dated 16th February 2010 and provided:

There the word "shall" is used instead of "must". It is absolutely clear that the direction was mandatory.

Also paragraph 12 of the order provided under the heading 'non-compliance':

In accordance with the directions a notice of experiments or notices were served in July and no party took any point as to whether they were outside the directions at the time that happened.

The next stage is September of 2010. On 24th September 2010, Mayer Brown (the solicitors for the claimant) wrote to Messrs Wragge & Co. (the solicitors for the defendant) and with the letter included what they describe as an "electron micrograph photograph". The letter ends with the sentence: "If you require any further assistance interpreting the enclosed photograph, please let us know."

At that stage the point, as I understand it, was that the claimant was contending that what one may or may not be able to discern from the electron micrograph was inconsistent with the Product Description in the state that it was at that time. The letter I have just referred to makes this point. It was being said that what the photograph showed suggested that the Product Description was inaccurate or incomplete in some way.

On 12th October Wragge & Co. replied and said, referring to the product description:

On 14th October Mayer Brown replied, dealing with this issue. They explained the point they were making in relation to the photographs. They said the electron micrographs showed that no fibrous material akin to melt blown polyurethane was visible in the micrograph. This was part of what appeared to be inconsistent with the Product Description. They concluded at page 3 of the letter:

On 25th October the defendant provided an Amended Product Description. Sure enough, it showed that the process that the defendant uses had been altered over time -- nothing wrong with that, I interpolate -- and it described an earlier process which was not the one that was in the original Product Description. This earlier one involved a degree of heating of the product in question. That can be seen in a letter of 25th October 2010.

At that stage, it became clear that in this case there are two forms of the product alleged to infringe, what we might call the "old form" and the "new form". The new form was the form that the defendant thought the case was about until this point in time, when it became clear that there were two kinds of product. Whether the difference is material or not of course is one of the issues that we will need to address. That was 25th October.

On 9th November, Messrs Wragge & Co. wrote to the claimant and, among other things, said this:

The point there is that at this stage it is now clear that the reason the electron micrographs were used in the first place, to show that there appeared to be some more information required in the Product Description, had borne fruit. The question any reader of this letter would appreciate was being asked was - were there any other matters that the claimant intended to use the electron micrographs for? If there were then there should be a Notice of Experiments.

In November 2010 -- the precise date does not matter -- Arnold J heard an application between these parties relating to experimental evidence. He decided that although the defendant had applied to exclude certain elements of the claimant's existing Notice of Experiments because they had not been repeated, the unrepeated parts could be admitted but would be a matter for submission at trial as to the weight to which the trial judge should attach to them.

One of the things that Dr. Turner (on behalf of the defendant) submits is that this was a perfect and appropriate time in which to have raised the dispute about the question of these micrographs and whether a Notice of Experiments should be served. Needless to say, no such matter was raised and the case continued.

Also in November the claimant served a notice to admit which sought admissions as to whether the old form of product infringed the claim or had certain elements to the claim. This was responded to on 7th December in a letter from Messrs Wragge & Co., which says as follows:

I should add here that the issue that all this goes to is whether the melt blown polyurethane in the defendant's old product is or is not a “carrier material” and satisfies the various requirements of claim 6 in this case. That is what this is all about.

On 9th December Wragge & Co. also wrote to clarify a further element of the product description about the degree of heating and the fact that infrared radiation had been used to heat the material.

Then on 10th December the parties exchanged their evidence, and a letter of 10th December from Mayer Brown (the claimant's solicitors) encloses by way of service an expert report of Stephen Clarson and one from Tomas Fabo, and also something they describe as the "claimant's notice of photographs", which consists of about 40 or 50 electron micrographs, which is what this application relates to.

The directions order of 16^th February 2010 had included the usual provision for a notice of photographs. It is called a "notice of models" etc., and in paragraph 7 it says:

As I understand it, it is not in dispute that if the electron micrographs in question are to be regarded as photographs, then good notice was given; but if they are to be regarded as experiments, then not. That is the point which the defendant took.

They wrote on 23rd December and said that the electron micrographs were experiments and that a witness repetition was required.

Ultimately the matter came before me on the morning of trial with the defendant applying to exclude the evidence and the claimants resisting that application.

The micrographs themselves consist of a series of 52 images which from a lay perspective look a lot like photographs. However, the defendant points out that what they actually are, sometimes properly called “electron micrographs”, is the result of scanning electron microscopy using various techniques in the electron microscope. This includes measuring back-scattered electrons after the electrons are bombarded on the material. Also in some cases, in particular photographs 10, 11 and 12 – they are false colour images which are supposed to show the presence of atoms of different elements. These are measured by analyzing the x-rays which the sample gives off after it has been bombarded by the electrons in the electron microscope. So photograph 10, which shows a purple and black image, shows, it is said, the distribution of carbon atoms in the sample. Photograph 11 shows the distribution of oxygen atoms. Photograph 12 shows the distribution of silicon atoms. This works because the x-ray frequency that is produced when the electrons bombard the sample is different, depending on whether the x-ray comes from a carbon, oxygen or silicon atom.

The claimant contends as part of its case why they should be admitted, and have put in evidence, that these images are formed using entirely standard electron microscope techniques. It seems to me on the evidence before me that it is fair to say that these are standard electron microscopic techniques. However, that does not answer the question as to whether they are or are not experiments.

The other matter that arises is the question of sample preparation. First of all, in terms of the scanning electron microscopy itself, in order to create these images it is necessary to coat the samples with carbon, and that is explained in one of the witness statements. In order to make the images at all, it is necessary to prepare the samples in this way.

Two particular further elements of sample preparation arise here. One is that the samples have to be cut with a scalpel. That may have a bearing on the issues because there is a question of contamination that I shall mention later. The other thing is that some of the images show a surface which has to be created by removing the silicone. These materials consist of layers of melt blown polyurethane and with silicone on top and in order to take some of the photographs -- I believe it is at least images 45 and 46 -- the silicone had to be removed.

The evidence that is relied on consists of a statement from the defendant's witness, Mr. McOmish. He was asked to address the question of whether this sort of technique required the exercise of judgment by the operator and to explain a little bit more about how these images would be created. His evidence is that judgment is required.

Then there is evidence which came in the day before trial from Mr. Eklund. He took the photographs or images in question and he explains how that was done, how the samples were prepared, dealing with peeling off the silicone gel and cutting with scalpels, and he also explains the degree of judgment which in his experience is required. His position is it would have been a routine operation for an experienced operator.

The first question, which Mr. Purvis described as a "technical" one, is the perhaps technical question of whether these are photographs or experiments. It seems to me absolutely plain that these represent experiments. I say that for a number of reasons. First of all, the point on judgment arises. It does seem to me that an exercise of judgment is required and that fits squarely into the judgment of Pumfrey J in Consafe Engineering v Emtunga. It also seems to me that it is a false dichotomy to say that something can either be a photograph or an experiment. These are obviously images and to that extent may or may not fall within what as a matter of English one might call a photograph. I am not going to get into the question of whether you need photons rather than electrons in order to make a photograph. It does not seem to me that is a sensible way of proceeding.

It is in my judgment absolutely plain as a pikestaff that this exercise of preparing these samples and then creating these images in a scanning electron microscope is an exercise which should have been the subject of a notice of experiments. I say that for a number of reasons.

The regime of notices of experiments is an important one. It is about avoiding surprise. It allows for the possibility of repeats. That is one element to it, but it also seems to me that it is about two further issues.

First of all, the notice regime requires a proper explanation of what the experiment was and it is clear to me that the first time the claimant explained exactly what they had done was yesterday. That is something which they simply could not have done if they had served a Notice of Experiments because the notice would have had to have explained what is now in Mr. Eklund's witness statement.

Secondly, the notice is also required to state the facts which the party seeks to establish. That is an important part of the notice of experiments regime because it is concerned with allowing the person receiving the notice to understand what it is that the party deploying the experiment is seeking to prove by the use of the experiment. That is highlighted in the correspondence in this case when it is absolutely clear that originally, and in my judgment, perfectly properly, the claimant was putting to the defendant the fact that it had these micrographs which appeared to be inconsistent with the Product Description and was pushing the defendant to explain the inconsistency. Indeed, that is exactly what happened, because the defendant then amended its Product Description to explain that the process in question had been changed over time, in the way that processes often are, and that no doubt explains the difference between what was being seen and what was being expected.

That also fits in with the letter that I mentioned in early November when the defendant asked the claimant whether it was going to serve a Notice of Experiments, because it does seem to me that the defendant was entitled to know what exactly it was that the claimant was seeking to prove with these images. It was only as a result of reading the experts' reports, served on 10th December, that that became clear. Indeed it can be seen, for example, at paragraph 63 of the claimants’ skeleton argument, that the electron micrographs are being used to support a case that the MBPU itself in the old product acts as a barrier to the silicone.

This is a highly material question. The issue is as follows. Claim 6 of the patent provides certain characteristics which must be satisfied by the carrier material. The defendant’s construction of claim 6 is such that the carrier material is the MBPU alone and they say that in the new product the MBPU alone is permeable and therefore outside the claim. Indeed I think it is fair to say that Mr. Purvis accepts that the MBPU alone in the new product is permeable, but the claimant says that the MBPU alone is not the right thing to look at when you are looking at the carrier material. They say the carrier material is the MBPU plus an acrylic adhesive. That is their case on the new product. But they also say in relation to the old product, and this is based to a large extent on the electron micrographs, that the MBPU alone is acting as a barrier and therefore infringes even on the defendant’s construction, which they do not accept. It seems to me that that is exactly the kind of point, expressed I hope more elegantly than I just have done, that ought to have been part of a notice of experiments.

In my judgment, these should have been the subject of a Notice of Experiments. Mr. Purvis, however, submitted that even if that was right I should still admit this material for a number of reasons. I need to deal with them.

He relied on the judgment of Pumfrey J in Monsanto and he pointed out that in paragraph 104 Pumfrey J recognised that there can be experimental evidence which is straightforward in respect of which the court will not make orders for repetition and inspection without a good reason. It may well be better to wait and see if good evidence or repetition by the other party throws doubt upon the result obtained before repetition is ordered. Mr Purvis submitted that this applies to the experiments in this case.

The defendant says that it relies on a different passage from Pumfrey J. It points out the particular anxiety that Pumfrey J expressed, that the regime for managing experimental evidence should not be weakened because there was nothing worse than poorly documented unrepeated experiments coming into proceedings at a late stage. I must say I found this an extremely difficult decision to make because it seems to me that it is absolutely vital that the regime for managing experimental evidence is not weakened. Nevertheless, it also seems to me that although the claimant, in my judgment, perfectly obviously should have served a Notice of Experiments, it also seems to me that it was not at all clear that it would have been necessary to order a repeat.

What should have happened is the notice of experiments should have been served. I am not sure whether a repetition would have been needed. At least it would have meant that the defendant knew where they stood and they could have dealt with it and called evidence in response, and maybe done their own micrographs or whatever. The trouble is that because of the way in which this matter has come before me that position is not as easy to organise as it might have been. The defendant of course says that that is all the claimant's fault and the right thing to do is to exclude the experiments.

At one stage in the argument I must confess it did seem to me that perhaps it was the right thing to do to exclude these experiments, but I am not going to do so. It seems to me that actually, looking at the matter in the round, the right thing to do is to admit this material while at the same time making it absolutely clear that it is vital that the regime for managing experimental evidence is not weakened and recognising that by letting in something which should have been the subject of the notice it might be said that I am doing precisely that. However, the factor that plays, in my judgment, as being the deciding factor is the way in which the defendant dealt with the question of infringement or non-infringement of this product.

Mr. Purvis submits that even after 10th December when the defendant served evidence in reply to the expert evidence from his client, which set out a case to say that the old product does infringe on this alternative basis, he was and remains in the dark as to exactly what the defendant’s case is. It does seem to me that the defendant is right that this should have been the subject of a notice, but that does not mean that they were then right to not deal at all with the question of whether the old product does or does not infringe. It seems to me that what should have happened is that this matter needed to come before a court before the morning of trial, but here it is and I have to deal with it.

I will admit this material. I do not believe a repeat is necessary. To that extent they are admitted on exactly the same basis that Arnold J admitted unrepeated experiments earlier in these proceedings; that is to say, the question of a lack of repeat will go to weight and I shall make it absolutely clear that that is a serious matter. It means that the parties need to be aware that it is possible that if it turns out, having heard the evidence, that a repeat really would have answered various questions, then the court may give these experiments no weight at all. However, it does seem to me that the right thing to do is to get on with this case and that is what I propose to do.

The final point is that I asked the defendant what it suggested should be done if I did admit these experiments. Mr. Turner had an alternative suggestion, which is that this evidence and the question of whether the new product should infringe could go off as a preliminary issue on an inquiry should an inquiry ever be necessary. Although that also sounds tempting, there are two reasons for not doing it. One is justice to all the parties in this case. The trial is happening now and I need to decide on what basis this trial is being conducted. Secondly, if the court decided, for example, and this is purely a hypothesis, that the patent was valid but was not infringed by the new product, there would not be an inquiry to decide whether or not the old product did infringe. Logically it is at least a possibility based on the arguments that arise.

So I will admit the experimental evidence reluctantly, I will not order a repeat and I will hear the parties as to the way forward.