THE scale of David Cameron’s task on EU reform has been underlined by No 10 after it indicated that not a single other member state was publicly supporting his four-year migrant benefit ban nor had any suggested an alternative to reduce the migration pull-factor.

Philip Hammond, the Foreign Secretary, urged other member states to come forward with alternatives, which Britain was ready to consider but, thus far, none, it seems, has.

The Prime Minister’s isolation, set to be underscored at a government leaders’ dinner this Thursday during the regular European Council in Brussels, has been laid bare as MPs in a report today warned that voters in the EU referendum should be made aware that there was "no certainty" of any agreed reforms ever being implemented.

The Commons European Scrutiny Committee, chaired by veteran arch-eurosceptic Tory Sir Bill Cash, said Mr Cameron's proposals would “not deliver the legally binding and irreversible agreement leading to reform of the EU nor a fundamental change in the UK's relationship's" he said that he wanted.

Plus, some elements, they pointed out, would require treaty change that could not be put in place or guaranteed for the future by December 2017, the deadline set by the PM for the UK's in/out vote.

Sir Bill stressed how treaty change would involve “lengthy processes” in some countries and each member state “would have to agree using its own constitutional procedures including, in some countries, referendums”.

Over the weekend, Mr Cameron’s position appeared to have shifted. While the UK Government maintained that his four-year welfare ban remained his key proposal, sources made clear if alternatives could be found that achieved the same end in reducing migration, then they would be seriously considered.

Mr Hammond, arriving in the Belgian capital for talks with EU foreign ministers, acknowledged other member states had raised "concerns" about the benefit curb but said that so far it was the only proposal on the table for dealing with the UK's worries about the level of migration.

Mr Cameron famously said he wanted to get annual net migration down to below 100,000; the latest figures show that it has hit a record of more than 300,000.

"So far,” admitted the Foreign Secretary, “we haven't heard any counter-proposals; we haven't heard any alternative suggestions that would deliver the same effect in a different way."

He added: "We have made very clear that if people have ideas that will deliver on this very important agenda for the British people we are absolutely prepared to listen to them and we are prepared to enter into a dialogue about them."

Earlier, No 10 stressed that what Mr Cameron was proposing was “significant far-reaching reforms” and that it was “going to take some work”.

The PM’s spokeswoman suggested progress had been made on other related areas such as tackling the export of child benefit, ensuring migrants who came to Britain were already in possession of a job and that over-stayers were being tackled.

But asked if there was a single EU partner who backed the PM’s proposal for a four-year ban on migrant benefits, she replied: “A number of countries…want to work with us to deliver changes in this area. We are now in the process of having detailed discussions about how those will work.”