Britain's ambassador to France has been nominated to be the UK's next and potentially last European Commissioner.
Sir Julian King has been put forward by David Cameron following last week's resignation of Lord Hill in the wake of the UK's vote to leave the EU.
Sir Julian, a career civil servant, will be interviewed by officials and MEPs before being offered the role.
Lord Hill was in charge of financial services but that job has now been given to Latvia's Valdis Dombrovskis.
The BBC understands that the new British commissioner is likely to be given a "less sensitive" post, potentially covering the environment.
The diplomat would take up his post at a time when the UK's relations with the EU are at an all-time low following the decision to end its 43-year membership of the organisation, previously known as the European Community.
Sir Julian is to be interviewed by EU Commission president Jean-Claude Juncker on Monday to assess his suitability for the post and will later face a "confirmation hearing" in front of the European Parliament.
Analysis by Damian Grammaticas, the BBC's Europe correspondent
Sir Julian King will, if accepted by the EU, fill an extremely delicate but highly influential position. The British Commissioner is the UK's most senior figure inside the EU institutions. A Commissioner does not represent their country, but he will be the eyes and ears of the UK, with a seat at the table as EU policy is drafted.
Crucially David Cameron's choice is not a politician, but one of the UK's most senior diplomats. Sir Julian King is currently ambassador to Paris. He knows the EU intimately. He's already filled three different diplomatic roles in Brussels.
He could face tough questioning in the European Parliament too before he can be confirmed. And it's not clear if Mr Juncker will give Sir Julian as high profile a portfolio as his predecessor Lord Jonathan Hill, who oversaw financial services in the EU but resigned following the referendum. Instead the UK's new Commissioner may get a less sensitive area such as environmental policy.
But having Sir Julian's experience in Brussels may prove crucial during future negotiations. French politicians have already indicated that the City of London will face tough conditions if the UK wants to enjoy its current level of access to Europe's Single Market.
According to the European Commission, new commissioners "shall be chosen on the grounds of their general competence and European commitment from persons whose independence is beyond doubt".
The approval of the European Council - made up of the 28 member states - is required before the appointment takes effect, while the Commission is also expected to "seriously consider" the opinion of the European Parliament.
If he is approved, Sir Julian will become one of the 28 top officials at the European Commission, the EU's executive arm. He would be expected to play an important role as a "conduit" between the UK and the other 27 member states during the talks over the UK's exit.
The UK remains a full member of the EU until it leaves, although it will not take part in all European Council meetings.
Mr Cameron has said it is up to the next prime minister, who will be elected in September, to decide when to trigger official exit talks - which, according to EU rules, should take two years although there remains controversy over the as yet untested Article 50 process.
Sir Julian only took up his current post in Paris in February. During a 30-year career in the diplomatic service, he held a number of senior positions in Brussels, including acting as a senior aide to a previous EU commissioner.
Previous UK commissioners have included high-profile political figures such as Lord Patten, Lord Kinnock and Lord Mandelson.