Video report by ITV News Political Correspondent Romilly Weeks
The government has been accused of "betraying" the British people's trust opting for an "inferior deal" if it hands over billions of pounds in a Brexit 'divorce bill'.
An urgent question on the costs of Brexit was granted to Labour's Chris Leslie following reports that the UK will agree to settle liabilities expected to total up to £49 billion.
Mr Leslie accused the government of paying for the privilege "of downgrading to an inferior deal" with the EU adding that the decision to withhold details of the UK's financial obligations was "losing control".
The government has dismissed the reported figure as "speculation" but Conservative backbenchers showed no signs of dissent in relation to the figures.
Speaking during a visit to Iraq on Wednesday, Theresa May refused to be drawn on the divorce bill reports.
When questioned by ITV News, the Prime Minister simply replied that the UK was "still in negotiations" with the European Union.
She continued that the amount the UK will pay to the EU when it leaves was "one of the elements that we've been looking at in this first phase of [Brexit] talks", adding that Britain wanted to ensure that the second round of negotiations would take place.
When pressed on the issue of Brexit negotiations, Mrs May referred back to her Florence speech in September in which she set out her plans for Brexit.
In Florence, the 61-year-old said she wants the UK to have a two-year transitional period and said it will honour its financial commitments up to 2020 as she laid out some of the key tenets of the Government's position.
Referring to the UK's financial commitments to the EU, Mrs May told ITV News "that nobody in the EU 27 needs to worry that they would have to pay in more or receive less through the current budget plan.
"I also said that we would honour our commitments, we're negotiating with the European Union 27, we're negotiating through obviously their negotiating team and Michel Barnier to look at those commitments, but we're still in negotiation with them."
Conservative backbencher and Brexit campaigner Jacob Rees-Mogg said that there was a "growing concern" that the government is "dancing to the tune of the European Commission in the negotiations.
Liz Truss, the chief secretary to the Treasury, said the Government was "not dancing to anyone's tune" adding it was important not to discuss specific figures during the negotiation.
Fellow Tory Peter Bone said: "The 60-odd percent of the people in Wellingborough who voted to leave would want to know what we were doing with £60 billion - they would want it spent on the NHS, social care and defence, they would not want it given to the European Union.
"Would the minister agree such a move would be betraying the trust of the British people?"
Tory former minister Robert Halfon said the Government risked undermining its argument on the "public sector and the need for good housekeeping" if the impression is given that "we have wads of cash and loads of money when it comes to Europe".
He added: "Does she not also agree that this is not a divorce bill; we are leaving a club and once you leave a club you no longer have to pay subscriptions?"
Ms Truss said: "The reality is that, as we leave the European Union, we will no longer be paying those vast sums of money in and that will represent a benefit to the taxpayer."
Her comments come after Brexit-backing Chris Grayling said it was "right and proper" for the UK to meets its financial obligations.
He added: "There's lots of speculation about figures at the moment. The reality is we've not completed the negotiations yet but we're very clear that we should meet the obligations that we've built up over the years of membership, that we should leave on good terms with our friends and neighbours."
Officials close to the negotiations were reported as saying there was broad agreement on a framework for the UK to settle liabilities expected to total around 45-55 billion euros (£40-£49 billion).
If confirmed, the move could clear the way for Prime Minister Theresa May to finally achieve her goal of moving Brexit negotiations on to the issue of trade.
However, the EU's chief negotiator Michel Barnier stressed "we are not there yet" when asked about Britain's divorce bill as well as an agreement on other issues.
He said that that there should be "sufficient progress" on citizens' rights and the Irish border before trade talks begin.
Speaking at the Berlin Security Conference, he said: "We are awaiting sufficient progress from London on the following three points: the rights of European citizens in the United Kingdom and of British citizens in the EU, issues relating to the border between Ireland and Northern Ireland, fulfilment of the financial obligations entered into during the United Kingdom's membership of the Union.
"We are not there yet.
"The work on the three main subjects continues this week in a constructive spirit with the UK.
"The next European Council will take place in 15 days' time. If real 'sufficient progress' is actually made, the European Council will be able to open the discussion of a possible transitional period.
"Then the member states will define in 2018 the framework of this new partnership with the UK."
Former Ukip leader Nigel Farage slammed the reported divorce bill as a "sellout".
"I have always argued that no deal is better than a bad deal," he said.
"Make no mistake about it - 55 billion euro to leave the EU is a very, very bad deal."
Former Cabinet minister Priti Patel also criticised the financial demands, saying on Monday that the EU should have been told to "sod off".
However, it is unlikely that the final settlement will ever be confirmed by the EU or the UK as it covers a complex array of liabilities from funding for projects to unpaid loans.
Unofficial calculations have put the gross figure at 100 billion euro (£88 billion) offset by deductions including the UK rebate and Britain's share of the European Investment Bank reducing the net some to half that.
Payments would be made over many years as liabilities fall due, so the final total may not be known for decades.
Liberal Democrat Brexit spokesman Tom Brake hit out at the settlement saying that it would hit the UK further after the country leaves the single market.
He said: "Around £45 billion would appear to be the price Johnson and Gove et al are willing to pay for a deluded vision of an imperial Britain post-Brexit.
"This vision already sees the UK with higher inflation and debt, falling investment and less influence in the world.
"And this acrimonious divorce settlement will merely be the down-payment."
In a letter to the EU's Brexit negotiator, Michel Barnier, the EU's Brexit coordinator, Guy Verhofstadt, wrote that he expected more concessions on citizens' rights and on the border between Northern Ireland and the Republic of Ireland.
The Belgian MEP wrote that while he recognised "that progress has been made since the start of the negotiations... considerable problems remain, which pose a fundamental question as to whether sufficient progress has been made".