EU officials have launched action against the UK for failing to name a new commissioner.
Each of the bloc’s 28 member states are required to nominate an EU commissioner to serve in the European Commission.
A new team, to be led by European Commission president-elect Ursula von der Leyen, is due to serve from 1 December.
However, the UK government said this week it will not nominate a UK candidate before the general election on 12 December.
The move has prompted Brussels to launch “infringement proceedings” against the UK and set a deadline of 22 November for Britain to respond.
In a statement, the European Commission revealed it had “sent a letter of formal notice to the UK for breaching its EU Treaty obligations by not suggesting a candidate for the post of EU Commissioner”.
“The UK authorities have until Friday 22 November at the latest to provide their views, “it added.
“This short time period is justified by the fact that the next commission must enter into office as soon as possible.”
In explaining the decision not to nominate a new UK commissioner prior to next month’s general election, a UK official stated that “pre-election guidance states the UK should not normally make nominations for international appointments during this period”.
It is understood the government does not intend to prevent the EU proceeding with the formation of a new commission, but is acting in line with long-standing pre-election advice agreed by Cabinet Secretary Mark Sedwill.
However, the EU disputed the UK’s suggestion that the upcoming general election should prevent the nomination of a new commissioner.
It stated: “The European Commission recalls that, in accordance with established EU case-law, a member state may not invoke provisions prevailing in its domestic legal system to justify failure to observe obligations arising under Union law. “
Under the terms of the latest delay to the UK’s departure from the EU – as a result of Prime Minister Boris Johnson’s request for a fresh three-month extension to the Article 50 negotiating period – the UK agreed to an obligation for nominating a candidate for a new commissioner.
Last week, the prime minister’s spokesman said the UK would “meet its legal obligations “with regards to naming a new commissioner, despite Mr Johnson’s previous vow not to nominate a new commissioner.
In July, during his first address to the House of Commons as prime min ister, Mr Johnson told MPs: “We will not nominate a UK commissioner for the new commission taking office on 1 December – under no circumstances – although clearly that is not intended to stop the EU appointing a new commission.”
Ms von der Leyen’s new commission has already been beset by problems after the European Parliament overwhelmingly rejected Sylvie Goulard as France’s nominee, in an embarassment for French President Emmanuel Macron.
Ms von der Leyen , who will replace outgoing commission president Jean-Claude Juncker, was also forced to alter the title of a new commissioner post, from “Protecting our European way of life” to “Promoting our European way of life”.
It followed criticism that the original title was offensive and a “dog-whistle” more akin to language used by far-right groups.