John Leeming

Partner, Patent Attorney, Litigator

John has over 25 years’ professional experience. He prosecutes patent applications in the optical, electronic and software fields, with particular expertise in semiconductor device manufacturing equipment and processes. John’s clients range from large multinationals to smaller start-ups, including firms that have successfully progressed beyond the early stages to develop extensive foreign filing programmes. Clients appreciate John’s pragmatic and cost-conscious approach to prosecution as well as his ability to effectively capture the essence of an invention in drafting applications.

John also handles litigation and enforcement matters, having conducted IPEC and Patents County Court proceedings and assisted in various Patents Court proceedings over the years. Many matters have been successfully resolved without recourse to litigation, sometimes making use of alternative dispute resolution methods such as mediation and IPO Opinions. John’s approach is to take clear and decisive action early in correspondence to prevent a matter escalating to litigation.

He also successfully handled, on behalf of the opponent, a reference to the European Patent Office Enlarged Board of Appeal (G0004/97) that established that it is legitimate to file an opposition in the name of a strawman. Other EPO opposition appeal proceedings John has handled include: T0414/96 (Gain v. Hashimoto) relating to injection molding; T0811/97 (Bosch v. Rifala) relating to inverting power supplies; T0503/98 (Cool Sorption & Callidus v. John Zink) relating to hydrocarbon vapour capture; T0359/99 (K’Nex v. Lego) relating to construction toys; and T0910/00 (ASML & Zeiss v Canon) relating to photolithography.  Ex parte appeals include T0546/95 and T0753/96 (Actel) relating to anti-fuses; J0016/02 (Vanderstraeten) relating to restitutio in integrum; T0408/04, T1896/09, and T1900/09 (Synaptics) relating to touch pads; T1533/05 and T0892/05 (ASML) relating to photolithography, T0787/06 (Sony) relating to web publishing and T0495/07 (Ricoh) relating to image processing.

John has extensive experience in recovering lapsed patents and applications, using restoration and restitutio procedures in the UK Intellectual Property Office (UK IPO), the EPO and elsewhere in Europe. The crucial factor in such proceedings is correct presentation of the evidence; viewed from the appropriate perspective an apparently hopeless case can become much more promising. He represented the proprietor in Ament’s Patent [1994] RPC 647 which overturned the UK IPO’s practice that lack of funds could never be a ground for restoration of an inadvertently lapsed patent.

The Legal 500 identifies John as a “Recommended individual”.

John joined J A Kemp in 1988 and became a partner in 1994.




University of Oxford, Masters Degree in Physics

Professional Qualifications

European Patent Attorney, UK Chartered Patent Attorney

Membership of Professional Bodies

Fellow of the Chartered Institute of Patent Attorneys (CIPA), Member of the Institute of Professional Representatives before the European Patent Office (EPI), Director and Deputy Chairman of PAMIA Limited (the UK patent attorney profession's mutual insurer), Member of the Union of European Practitioners in Intellectual Property (UNION), Member of the Society for Computers and the Law

Contact John

If you wish to talk to John Leeming, please send an email directly to

or call +44 20 3077 8600

Can We Help You?