Theresa May has played down the prospects of an “immediate breakthrough” on the so-called Northern Ireland backstop in talks with EU leaders.

The Prime Minister arrived in Brussels after surviving a bruising vote of confidence by Tory MPs, saying she would be looking for fresh assurances to help get her Brexit deal “over the line” in Parliament.

However, she acknowledged there was a limit to the progress she could make on the issue which has turned so many of her MPs against her during the two-day EU summit meeting.

“My focus now is on ensuring that I can get those assurances that we need to get this deal over the line, because I genuinely believe it’s in the best interests of both sides – the UK and the EU – to get the deal over the line, to agree a deal,” she said.

“But I recognise the strength of concern in the House of Commons and that’s what I will be pushing to colleagues today.

“I don’t expect an immediate breakthrough, but what I do hope is that we can start work as quickly as possible on the assurances that are necessary.”

After being forced to pull a crucial Commons vote on the Withdrawal Agreement earlier this week, Mrs May has acknowledged she needs further concessions from Brussels if she is to win over enough MPs.

Many MPs remain concerned the UK could be tied to EU customs arrangements for years if the backstop – intended to ensure there is no return of a hard border on the island of Ireland – is ever activated.

Reports from Brussels suggest EU leaders are considering a draft document stating the bloc “stands ready to examine whether any further assurance can be provided” to the UK on the backstop.

It said that if the backstop was ever activated the EU would seek to ensure it “would only be in place for a short period and only as long as strictly necessary”.

But such assurances are unlikely to satisfy hardline Brexiteers who have been demanding the backstop is dropped altogether.

EU leaders arriving for the meeting insisted that while they want to be helpful to Mrs May, they are not prepared to reopen negotiations on the Withdrawal Agreement.

Luxembourg prime minister Xavier Bettel, who was holding one-to-one talks with Mrs May ahead of the main summit, insisted significant changes to the agreement would not be possible.

“We won’t be able to do genuine changes. Renegotiating will be very, very hard, but if we need to do precisions or help Theresa May – I really want to help her,” he said.

BrexitTheresa May, left, speaks with Luxembourg’s Prime Minister Xavier Bettel (Geert Vanden Wijngaert/AP)

German Chancellor Angela Merkel was also adamant the Withdrawal Agreement could not be changed.

“We can discuss whether there should be additional assurances, but here the 27 member states will act very much in common and make their interests very clear,” she said.

Dutch prime minister Mark Rutte, who met Mrs May in The Hague on Tuesday, said they need to “demystify” the backstop, making clear there is no desire in the EU for it to be activated.

“It will be impossible to break open the negotiated Withdrawal Agreement. That is a given. We have to seek clarifications on what is needed particularly on the backstop,” he said.

“There is now this whole thinking in the UK at the backstop is inevitable. There is nobody in his right mind in the European Union who wants to trigger the backstop because it is bad news not only for the UK but for the EU.”

Asked if it is possible to provide legally-binding assurances to meet UK concerns, he said: “That depends on what you mean on legal. That is very difficult if you are not going to break open the Withdrawal Agreement.”

Labour leader Jeremy Corbyn said:  “It is clear there will be no changes to the deal the Prime Minister brought back last month. Theresa May herself says she isn’t expecting a breakthrough.

“There must be no more dither and delay, or attempts to run down the clock in an attempt to deny Parliament alternative options.

“People and businesses need certainty. The Prime Minister should put her deal before Parliament next week in our country’s interest.

“She has admitted her deal is likely to be defeated by a significant margin. There is no time to waste, and parliament must take back control.”