European Commission head Jean-Claude Juncker on Wednesday appointed veteran French politician and former EU commissioner Michel Barnier to lead the negotiations with Britain on its exit from the bloc.
Britain's June 23 vote to quit the 28-nation European Union shocked EU leaders who had bet on a vote to remain but they have since rallied, with France and the Commission leading demands that negotiations should begin as soon as possible.
"I am very glad that my friend Michel Barnier accepted this important and challenging task. I wanted an experienced politician for this difficult job," Juncker said in a statement.
"I am sure that he will live up to this new challenge and help us to develop a new partnership with the United Kingdom" after it becomes the first country to leave the EU.
Barnier held the key Commission financial services portfolio from 2010 to 2014, spearheading efforts to tame the eurozone debt crisis which nearly brought down the single currency project.
He was also central to efforts to save the EU's stricken banks, laying down tough new rules to police a new banking union system which often put him at loggerheads with the City of London, one of the world's top financial markets.
Jacques Lafitte of the Avisa investment advisory group said the appointment sent a very clear message of intent to Britain.
"After all these years that the City has demonised Michel Barnier, often unjustly, the Commission could not have sent a firmer message to the English," Lafitte told AFP.
New British Prime Minister Theresa May has made clear London will not be rushed into the Brexit talks which are widely expected to begin early next year.
May insists she wants Britain to keep the fullest access possible to the bloc's single market of 500 million people while at the same time having the right to limit EU migrants, the key issue which turned the referendum.
Juncker and EU leaders agree that close ties with the world's fifth largest economy are in the interests of both sides but they also insist they will not accept limits on the free movement of people, a core EU principle.
Juncker has repeatedly stressed the need to get the talks underway as soon as possible so as to end the uncertainty over both Britain's and the bloc's future.
Barnier takes up his position on October 1 but the Brexit talks can only begin once Britain invokes Article 50 of the Lisbon treaty, which sets the clock ticking on two-years of divorce talks.
If the talks fail to produce an agreement, Britain will end up leaving the EU unceremoniously and be treated as any other country under World Trade Organization rules.
Barnier previously served as EU commissioner for regional policy and had stints as both French foreign and agriculture minister.
Barnier tweeted he was "honoured to be entrusted UK negotiation by @JunckerEU and @EU Commission. Rendez-vous for beginning of demanding task on 1 October."
Juncker said Barnier was a "skilled negotiator with rich experience in major policy areas relevant to the negotiations (and) ... has an extensive network of contacts."
"He will report directly to me and I will invite him to brief regularly the (commissioners) to keep my team abreast of the negotiations," he added.