Theresa May has reportedly chosen Friday August 30th 2019 as the day she will step down from 10 Downing Street

Number 10 has dismissed claims Theresa May is going to quit as Prime Minister as 'peak silly season'.

Their denial comes amid reports the PM had selected a date - Friday, August 30 2019 - as when she would step down.

Mrs May has launched a major charm offensive to win back the support of her MPs - and the public - to avoid an awkward leadership challenge.

After inviting a group of 15 Tories to her official Chequers country residence for prosecco and chocolates, a report surfaced that she was giving herself a deadline of two years to complete Brexit negotiations.

But today a spokesman for the Prime Minister told MailOnline the claims were rubbish.

Already more than a dozen Conservative politicians are said to have pledged to sign a letter calling for Mrs May to step down - although that falls far short of the 48 signatures needed to trigger a new leadership vote.

One Tory MP said: 'It's clear she won't lead us into another election and will be gone by September 2019.

'She invited MPs to Chequers to ensure there isn't a ­leadership contest in the meantime.

'Giving the dogs a stroke is better than giving them a kick, I suppose.'

It earlier emerged that Brexit secretary David Davis is set to provoke a huge row with Brussels by calling a halt to negotiations on Britain's divorce bill unless the EU provides a legal basis for its hefty demands.

It comes amid a major charm offensive by Mrs May in a bid to win the support of her MPs and avoid an awkward leadership challenge. The Prime Minister has been inviting groups of 15 Tories to her official Chequers country residence

The European Commission's chief negotiator Michel Barnier has warned that Britain must be ready to set out what it is willing to pay when the next round of talks begin on Monday in Brussels.

But Mr Davis will snub his request and refuse further discussions on the demand, thought to be for around £74billion, until the EU shows the legal justification for it.

As tensions between the two sides escalated, Brussels accused Britai of 'magical thinking' over Brexit and suggested ministers were willing to use the Northern Ireland peace process as a bargaining chip in negotiations.

Possible contenders? Boris Johnson and Phillip Hammond - is not clear if they are at Chequers

The EU has warned that Brexit talks will be paralysed unless Britain puts forward details of out how it thinks the divorce bill should be worked out.

Mr Barnier is under orders from the 27 remaining EU countries that discussions on a future trade deal with Britain cannot begin until 'sufficient progress' is made on the bill, the rights of EU citizens living in the UK and Northern Ireland.

However, British officials believe Brussels will be forced into a climbdown as they think EU leaders will face a backlash from European businesses if they attempt to stall trade talks.

A Whitehall source said: 'It's not just British businesses that want certainty. Firms in Germany, France and across Europe will be lobbying their governments to get on with working towards a trade deal.'

Foreign Secretary Boris Johnson, who said recently that Brussels should 'go whistle' over the divorce bill, told Radio 4's Today programme that Britain will meet its legal obligations to the bloc but will pay 'not a penny more, not a penny less' than it has to.

One EU official said there was a risk that Brexit talks could completely break down if progress is not made on agreeing the bill sooner rather than later.

The official said: 'During the last round we made no progress. The UK recognised they have financial obligations but did not engage in identification of what these will be.'