Brexit Secretary David Davis has turned the European Union's negotiating mantra against the bloc to warn that it cannot cherry pick the terms of a free trade deal.
Britain wants "the full sweep of economic cooperation" and financial services must not be excluded from any agreement, Mr Davis said.
EU chief negotiator Michel Barnier has repeatedly insisted the UK cannot choose to keep the best elements of membership when it quits the bloc.
No trade agreement exists that includes financial services and the City of London will inevitably face curbs on access, he has warned.
But Mr Davis said a deal that took some areas of the current economic relationship but not others would be "cherry picking".
In an article for the Daily Telegraph, Mr Davis wrote: "I do not believe the strength of this cooperation needs change because we are leaving the European Union.
"Many of these principles can be applied to services trade too. Given the strength and breadth of the pan-European economic relationship, a deal that took in some areas of our economic relationship but not others would be, in the favoured phrase of EU diplomats, cherry picking."
The Government is under pressure to provide more clarity for business as the new phase of exit talks begin.
EU leaders in the rest of the bloc remained united during the first stage of negotiations, but the bond could be tested as the bloc considers what kind of trading terms are on offer to the UK - an important export market for many member states.