FILE PHOTO: Britain's Prime Minister Boris Johnson speaks during a lawmakers meeting to elect a speaker, in London, Britain December 17, 2019. ©UK Parliament/Jessica Taylor/Handout via REUTERS

LONDON (Reuters) - Prime Minister Boris Johnson will tell European Commission Chief Ursula von der Leyen that Britain will not extend its transition out of the European Union beyond Dec. 2020, and is not seeking a new relationship based on alignment with existing rules.

The British leader is due to meet von der Leyen in London on Wednesday for the first time since the commission president, who will play a pivotal role in talks to thrash out new arrangements between Britain and the EU, took office in December.

Johnson won an election last month by promising to deliver Brexit on Jan. 31 and use an 11-month transition period to negotiate a deal that will define terms between the world’s fifth-largest economy and its biggest trading partner.

A statement from Johnson’s office ahead of the visit said he would “stress the importance of agreeing a confident and positive future relationship by the end of December 2020.”

It added: “The prime minister will likely underline that the upcoming negotiations will be based on an ambitious FTA (Free-Trade Agreement), not on alignment.”

Von der Leyen has previously cast doubt on the chances of concluding such a complicated trade agreement within a relatively short space of time, with similar deals having taken years to thrash out and implement.

British Brexit minister Stephen Barclay, and EU Brexit negotiator Michel Barnier will also take part in the meeting.