David Cameron yesterday hailed a draft deal to keep the UK in the European Union, but was almost immediately forced to warn rebels in his own cabinet against fighting for a 'Brexit'.

The Prime Minister welcomed the proposals, which he said delivered on the promises in the Conservative's election manifesto.

But that provoked a furious outcry from critics who claimed they fell far short of his original aims.

In extraordinary scenes in the Commons one Conservative MP even accused a Tory minister of “polishing poo”.

There was also an outcry north of the Border as the SNP stepped up its campaign to thwart a June referendum, warning it risked clashing with May's Holyrood elections.

In a speech less than an hour after the framework document was published, Mr Cameron all but confirmed he would campaign for the UK to stay in the EU.

The Tory leader said that the deal, drawn up by officials in Brussels and London, was a “very strong and powerful” renegotiation of the UK's relationship with Europe.

“If I could get these terms of British membership, I sure would opt in,” he said.

He said his aim had been to secure reform in four areas - reducing migrants’ access to benefits, protections for non-euro countries, sovereignty and competitiveness.

“All of those things have been addressed in a proper way in this document," he added.

He also hinted that there could be more concessions before a crunch meeting of European leaders in a fortnight.

All 28 members states have to agree to the reforms before they can be put to a vote in the UK.

But Mr Cameron hinted at a June referendum, suggesting polling day was "potentially a few months" away.

No 10 fear a delay would give succour to the 'Out' campaign because of the growing migrant crisis affecting Europe.

Earlier, Mr Cameron had reminded his cabinet that they were bound by collective responsibility not to speak out against his proposals until after the European summit.

Mr Cameron has told his ministers they can campaign to leave the EU only once his renegotiations are complete.

Opponents accused the Prime Minister of giving himself a two week headstart in the fight for the UK's future.

Critics also complained that, unlike his manifesto pledges, Cameron had failed to obtain a four-year ban on in-work benefits or a complete block on EU migrants sending child benefit payments abroad.

Instead, Mr Cameron secured an 'emergency brake', which allows the UK to prevent access to in-work welfare payments, if it can prove that the system is under intolerable pressure because of immigration.

In future, child benefit payments will also be calculated according to the welfare rates in the European country where the children live.

There was also a withering response to a proposed ‘red card’ system - which allows member states to band together to block legislation proposed by the European Commission, if enough of them agree.

Some Tories were scathing about the results of his diplomacy.

Steve Baker, the co-chairman of Conservatives for Britain, told the Europe minister David Lidington in the Commons that he had been reduced to “polishing poo”.

He added: “This in-at-all-costs deal looks funny, it smells funny, it might be superficially shiny on the outside but poke it and it’s soft in the middle."

Ukip leader Nigel Farage called the concessions "pathetic".

SNP Westminster leader Angus Robertson called for a June referendum to be ruled out.

Holyrood's Europe Minister Fiona Hyslop said: "We have not been consulted on the detail of these latest proposals so will need time to study them and their implications for Scotland. But if we are to influence positive change in Europe, we must preserve our EU membership."

She added that she was "strongly opposed" to a June referendum.

Business for Scotland called for a separate 'red card' north of the Border to prevent the UK leaving the EU unless all four nations backed it in the referendum.

Liberal Democrat leader Tim Farron hit out at the SNP's call for a delay saying: "They are, for their own agendas working to destabilise the economy and paralyse politics."