The German lawyer whose court action has put the new European patent regime on hold has described as ‘astonishing’ the UK’s apparent position that it can be a member of the system after Brexit.

Düsseldorf intellectual property attorney Dr Ingve Stjerna says the government’s stated plan to ratify the Unified Patent Court agreement appears ‘hardly reconcilable’ with its commitment to leave the jurisdiction of the Court of Justice of the European Union.

‘At the very least, an explanation is needed why in case of the UPC the creation of new obligations from union law and respective powers for the CJEU as well as a respective liability of the UK for union law violations are deemed acceptable, despite the envisaged objectives for leaving the EU,’ Stjerna said on his website.

Stjerna is the originator of a case brought before Germany’s federal constitutional court against the Unified Patent Court agreement. The court last week announced an extension to its deadline for accepting comments on the credibility of the case, meaning that German ratification of the agreement remains on hold.

Germany, along with France and the UK, must ratify the agreement before it becomes law, establishing a new unified patent and courts system, one arm of which is planned to be in London. The constitutional court deadline extension to 31 December kills any chance of the agreement coming into force this year.

Stjerna’s challenge questions the constitutionality of the German legislation enabling ratification. It also alleges a violation of a requirement under German law which stipulates that a majority of two-thirds of the members of the German parliament and Federal Council must rule on any transfer of sovereign powers to European institutions.

The UPC, which will hear disputes related to unitary patents, has been beset with delays. One of the court’s major divisions is set to be housed in Aldgate Tower on the edge of the City of London. It will have to refer certain matters to the CJEU which will act as court of appeal on matters centred on EU law.

Westminster is to debate a statutory instrument that will give the UK arm of the court ‘legal personality’ in the coming weeks.