Michel Barnier, the bloc’s chief negotiator, is understood to have pencilled in June 19 as the first day for detailed talks on Britain’s departure from the bloc.
The session is expected to kick off weeks of intense wrangling over the UK’s future relationship with the EU during the summer.
The decision on the timing of the talks, set to be confirmed by the European Commission on Monday, means the Prime Minister will be pitched straight into the battle for the country’s future within days of polling day on June 8.
Senior Tories are certain to argue that the imminent talks show the urgent need for “strong and stable leadership” to ensure the Government gets the best possible outcome from the negotiations.
Ministers from the 27 other EU nations are due to meet on Monday to confirm the timetable for the talks.
“The 19th is the earliest date they can envisage.”
News of the date comes a day after EU Exit Secretary David Davis told the Daily Express that Theresa May had shown the Government “means business” and will not put up with “silly games” by Brussels if she returns to Downing Street after the general election.
In an exclusive interview, the Tory Cabinet minister warned that a “tense period” was ahead in the negotiations.
Mr Davis also rubbished the idea that Britain could be forced to pay up to £85billion to leave the EU.
In previously unpublished remarks from his Daily Express interview, the EU Exit Secretary said: “Picking numbers out the air doesn’t work. I’m not going to do the negotiation in public anyway.
“What is plain is that the period of paying over vast sums of money into the EU is coming to an end – that is the most important thing.”
He added: “We have said we will talk to them. We will meet our obligations. One of our great reputations globally is that we meet our obligations whatever they may be.
“We’re going to have a very careful look. The numbers you see banded around, they are not legal obligations.
“We want to be friendly with these people in the long run. These are our markets, it’s not in our interests to destabilise them.
“It is not in our interests to treat our allies badly, but on the other hand it’s also not in our interests to hand over a load of taxpayers’ money.”
Mr Barnier told European Commission officials earlier this month that the EU will focus on securing citizens’ rights, financial issues and borders in the talks
He has expressed hopes for a preliminary deal on these issues to be concluded between October and December.
If that timetable holds, the EU would be ready to start discussing the shape of its future trade relationship with Britain and a transition period leading to it between December 2017 and spring 2018.
Mr Barnier has proposed that his face-to-face talks with Mr Davis will be held in four-weekly cycles.
The first week would be devoted to preparations by the 27 governments and the European Parliament and the second to an exchange of documents with Britain.
The third week would be for negotiations themselves – EU officials expect the British to come to Brussels for the week – and the fourth to report the results to the 27 governments and the European Parliament and prepare the next round of talks.