Scope of Mental Act Exclusion Clarified and Reduced

Mental acts are one of the items excluded from patentability under Article 52(2) EPC, along with computer programs, business methods, etc. These things (“as such”) are considered not to be inventions, and hence represent non-statutory subject matter for the purposes of European patent law. The same list of exclusions is present in UK national law, although the UK Courts have tended to adopt a somewhat different approach to non-statutory subject matter from the European Patent Office (EPO). The UK Courts generally attribute more weight to the specific individual items listed in Article 52(2) EPC (and corresponding section 1(2) of UK national law); in contrast, the EPO tends to ignore the details of the individual exclusions in favour of an umbrella approach in which anything ‘non- technical’ falls outside the scope of patentability.

Historically, the UK Courts have had some difficulty determining the exact boundaries of the Article 52(2) exclusions, no more so than for the mental act exclusion. UK case law has developed two possible interpretations of ‘a method for performing a mental act’. The first interpretation, generally referred to as the narrow view, is that the exclusion only covers an act that is actually performed in the mind. According to this narrow view, any computer-implemented method necessarily falls outside the scope of the exclusion, since the method is performed by the computer (not in the mind). Alternatively, there is the broad view, in which the exclusion covers an act that could, in theory, be performed in the mind, even if the claim is limited to exclude such a possibility, eg, even if the claimed method is explicitly restricted to a computer implementation.

The case law regarding excluded subject matter was reviewed extensively in the Aerotel decision in 2006 from the Court of Appeal. Although the mental act exclusion was not at issue in that case, the Court made the obiter comment that:

we are doubtful as to whether the exclusion extends to electronic means of doing what could otherwise be done mentally.

Following the decision in Aerotel, the UK Intellectual Property Office (UK IPO) issued a revised practice notice on how it would handle excluded subject matter. This advised that although the comments of the Court of Appeal regarding the mental act exclusion were obiter:

examiners will lean towards the view expressed in the current judgment, on the grounds that this is probably a better reflection of current judicial thinking.

Shortly after Aerotel, the UK High Court did specifically consider the scope of the mental act exclusion in the Kapur decision. In this case, the Judge came down clearly on the side of the narrow interpretation:

In my judgement the narrow view of the exclusion is the correct one.

Unfortunately however, Kapur was soon followed by another decision from the Court of Appeal, Symbian, which again considered non-statutory subject matter. As with Aerotel, the Symbian case was not specifically concerned with the mental act exclusion, but nevertheless it contains some obiter comments that appear to support the broad interpretation. Certainly this was how the UK IPO understood Symbian, since it issued a further practice notice which reverted back to the broad interpretation.

Actually, there are a number of comments about the mental act exclusion in Symbian, and some of them appear to favour the narrow interpretation rather than the broad interpretation. Also, it is doubtful whether the UK IPO was at liberty to follow selected obiter comments in Symbian, rather than the apparently binding decision of Kapur (even though Symbian was from a higher court). Nevertheless, the UK IPO took the broad interpretation of the mental act exclusion, as set out in the practice notice, when rejecting four patent applications filed by Halliburton, which concerned, inter alia, improving the design of roller cone drill bits for drilling oil wells.

In fact, Halliburton are no strangers to the issue of non-statutory subject matter in the UK Courts. Back in 2005, the UK High Court had held another Halliburton case, also relating to the design of drill bits, to represent excluded subject matter. In that case, the Court approved an EPO decision, T0453/91, concerning the design of a VLSI-chip. In T0453/91 the EPO Board of Appeal had rejected claims to the design method itself, but then allowed claims which had been amended to include “and materially producing the chip so designed”, ie, to include the physical manufacturing step for the designed product.

However, since the Halliburton case in 2005, there has been a further decision from the EPO, T1227/05, which departs from the decision in T0453/91. This second case allowed claims to a computer-implemented method for the numerical simulation of a circuit. The Board felt that such simulation was now very much a ‘technical’ activity, and hence should be open to patentability.

These were the circumstances that confronted Judge Birss when he heard the appeal by Halliburton against the rejection of their four applications. The Judge was unusually well-acquainted with the case law in this area, having represented the UK IPO (as a barrister) in the Aerotel case. His decision was unequivocal:

the balance of authority in England is in favour of the narrow approach to the mental act exclusion.

He further confirmed that he would also:

favour the narrow interpretation on its own merits,

And seemed generally comfortable with the EPO approach set out in T1227/05.

Accordingly, the Judge overturned the refusal by the UK IPO, and allowed the Halliburton applications, and further observed that he thought the practice notice issued after Symbian was wrong as regards the mental act exclusion.

Since the decision in Halliburton, the UK IPO has issued a brief practice notice indicating that they will now follow the narrow interpretation of the mental act exclusion. For practitioners, this represents a sensible and welcome (and overdue!) outcome.

Useful links

Halliburton Energy Services Inc [2011] EWHC 2508 (Pat) (05 October 2011)
Aerotel Ltd v Telco Holdings Ltd & Ors Rev 1 [2006] EWCA Civ 1371 (27 October 2006)
Kapur v Comptroller General of Patents, Designs & Trade Marks [2008] EWHC 649 (Pat) (10 April 2008)
Symbian Ltd v Comptroller General of Patents [2008] EWCA Civ 1066 (08 October 2008)
T0453/91
T1227/05