Brussels is confident it has secured a deal to keep the UK in the European Union – setting the scene for a possible June referendum.

Details of the proposed reforms are due to be circulated to European leaders at noon today, increasing Prime Minister David Cameron's chances of reaching an agreement with other EU states that would allow him to hold a pre-summer poll on Britain's membership.

No 10 fears that with the migrant crisis affecting Europe any delay could increase the chances of an 'Out' vote.

But First Minister Nicola Sturgeon has warned that campaigning for a June poll could clash with May's Holyrood elections.

Today (Tues) a cross-party group of MPs publish a motion calling on the Prime Minister not to hold the In-Out referendum in June.

European Council president Donald Tusk will table the proposed new settlement for the UK, following what he described as "good progress" in talks, later today.

The framework deal will be the subject of talks at a crunch summit of EU leaders on February 18.

However, in a sign that of potential problems ahead Mr Tusk admitted that "outstanding issues" remain.

Downing Street also predicted a "lot of hard work" would be needed to persuade the other 27 EU member states to sign up to its reforms.

Former Polish foreign minister Radek Sikorski, warned that his government would pay a ‘high political price at home’ if it did not block the so-called ‘emergency brake’ on benefits.

The UK is understood to have secured agreement that the UK can apply the 'brake', and prevent migrants accessing benefits, immediately after a 'Stay' vote, because of existing immigration levels.

But questions remain over how the system would work and how long it would last.

No 10 said that the key test would be that it did not deliver less than Mr Cameron’s original proposal – an outright four-year ban on new migrants claiming benefits.

Other European countries protested against that idea, however, denouncing it as discriminatory.

Other proposals on the table are thought to include reforms to prevent 'sham' marriages in which one party is from the EU.

Sources said it was just one of the changes proposed by the UK that would benefit other all EU countries.

Meanwhile, a cross-party group, including MPs from the SNP, Labour, the Conservatives, the DUP and the SDLP, have signed a motion against a June vote.

The SNP's Europe spokesman, Stephen Gethins, who tabled the motion at Westminster, said: "Those MPs who have signed this motion may have different views about the UK’s future membership of the EU but we agree that there should be a proper debate.

"One of the many lessons of the Scottish independence referendum was the importance of having a debate in which people were engaged and could have their say.

"To do anything other with the EU referendum has to be resisted."

June 23 is thought to be the Prime Minister’s preferred date, before the start of the Scottish school holidays, which begin slightly earlier than those in England Wales and Northern Ireland.

UKIP accused the Prime Minister of attempting “panto”, attacking the "theatrics and drama of his sham renegotiation".

Mr Cameron himself met with Tory backbenchers, urging them that it was important to “keep the party together”

However, a new survey suggests that one in five Conservative MPs will vote for Britain to leave, regardless of the outcome of the negotiations.

The vast majority, 61 per cent of those who took part, said that they would decide after a deal was reached.

Former Commons deputy speaker and Conservative MP Nigel Evans warned that the UK could not be expected to ask 27 others “to decide that we can put our foot on the brake. No driver in their right mind would get into a car with those sorts of conditions."

Former cabinet minister Peter Lilley suggested a temporary emergency brake would lead to legal challenges.

Meanwhile, Jen Stoltenberg, Secretary-General of Nato, warned that the UK was safer within the EU.

It was also reported that France has warned that it will block any attempt to secure veto to protect the City of London.