David Cameron has said he is "happy to be judged" on the outcome of his renegotiation of Britain's EU membership, amid Eurosceptic claims that it falls short of manifesto pledges to ban migrant benefits and restore British sovereignty.
The Prime Minister faced criticism from the Tory backbenches as he set out proposed reforms in the House of Commons, with Jacob Rees-Mogg complaining that the "thin gruel" on offer had been "further watered down", while Sir Bill Cash claimed Mr Cameron had "bypassed" his principles and promises.
Mr Cameron acknowledged that further work will be needed to secure reform in an "intense" round of negotiations ahead of the February 18 EU summit, but told MPs the plans put forward by European Council president Donald Tusk on Tuesday were the strongest ever achieved on freedom of movement rules.
Mr Cameron said: "I believe we are making real progress in all four areas but the process is far from over. There are details that still need to be pinned down and intense negotiations to try and agree the deal with 27 other countries.
"It will require hard work, determination and patience to see it through but I believe that with these draft texts and with all the work we have done with our European partners Britain is getting closer to the decision point."
He later told Sky News: "I am very happy to be judged on what we set out in our manifesto and what we've achieved."
Mr Cameron added: "There are the issues that Britain has had the biggest trouble with in Europe - that it's too bureaucratic, it's too much of a political union, there's not a fairness between eurozone and non-eurozone countries, and also the problems of migration.
"All those four issues are addressed, to an extent, by the negotiations that we look like we will be able to achieve with further hard work."
Mr Cameron said he had "sorted" two welfare pledges, to deny EU migrants unemployment benefit and require them to return home after six months if they do not find a job. And he said that, while he had not secured a ban on child benefit payments to offspring abroad, it would be paid at local rates rather than the more generous UK level. And he said that, having promised to ban migrants from accessing welfare for four years, he had achieved "four years until full access".
"I would say judge me on those things," he said. "They are substantial, they are meaningful. They are not the final word, but I think they do make a difference, particularly on this key value that we don't believe in something for nothing."
In Strasbourg, European Commission president Jean-Claude Juncker hailed the draft deal as "fair for the UK and fair for the other 27 member states".
But he risked antagonising Eurosceptics by saying that the euro "remains the currency of the EU", and that a proposed emergency brake on migrant benefits will be "limited in time" and would apply only in "exceptional circumstances".
And former Belgian prime minister Guy Verhofstadt angered British MEPs by claiming the UK would be a "dwarf" if it votes in the forthcoming referendum to leave the EU.
Former defence secretary Liam Fox predicted up to five Cabinet ministers will back Brexit in the referendum, and warned that the Prime Minister risks creating a lasting split in the Conservative Party if he tries to gag them from speaking out any longer.
Boris Johnson - tipped as a possible leader of the Brexit campaign - stayed on the European fence, but has said that there is "a lot more to do" before he can back the Tusk reforms and said the PM was "making the best of a bad job".
Mr Cameron defended his decision to allow Cabinet ministers to campaign on both sides of the referendum debate once the renegotiation is complete, telling Sky: "To pretend that businesses or families or political parties all have to be on the same side on this, I don't think is right."
Labour leader Jeremy Corbyn confirmed that Labour remained committed to keeping Britain in the EU but dismissed Mr Cameron's renegotiation as a "Tory Party drama".
"For all the sound and fury, the Prime Minister has ended up exactly where he knew he would be, making the case to remain in Europe, which was what he always intended despite a renegotiated spectacle choreographed for TV cameras over the continent," he told the House of Commons.
Mr Cameron is expected to seek opportunities to discuss the EU reform package with the prime ministers of Belgium, Greece, Sweden and Slovakia in the margins of Thursday's Syria donors' conference in London, said Downing Street.