The fragile Tory truce over Brexit has been shattered after Theresa May admitted there is “no suggestion” of scrapping the Irish backstop – triggering fresh anger from her anti-EU MPs.

Under pressure from business leaders in Belfast, the prime minister let slip that she will only seek “changes” to the controversial backstop – not its removal – in fresh talks in Brussels on Thursday.

The comment was seen as backtracking on last week’s Commons vote that it should be “replaced with alternative arrangements”, which Ms May had ordered Conservative MPs to support.

The reaction from the hardline European Research Group (ERG) of Tory MPs was swift, with one source saying: “Even if she doesn’t mean what she said, we still do.”

One prominent Brexiteer, John Whittingdale, pointed out the prime minister had set up a “working party” to explore ideas leading to trade deal that “would not need the backstop”.

“That’s the kind of alternative that it is in the interest not just of Northern Ireland but the United Kingdom as a whole,” the former cabinet minister said.

Arlene Foster, the leader of the Democratic Unionist Party (DUP), which props up the Tories in power, said the backstop had to be axed.

“It’s very important that we replace that backstop – that we deal with it – because, currently, it creates a hard border between Northern Ireland and the rest of the United Kingdom, and that’s totally unacceptable.”

The ERG will restate its determination to replace the backstop with – unproven – technology at an event on Wednesday, as the prime minister holds talks with the Northern Ireland parties.

On Thursday, Ms May will meet EU leaders in Brussels for the first time since the crushing defeat of her deal in last month’s “meaningful vote”, but with no specific proposal to break the deadlock.

How Brexit will affect your travel to Europe Show all 14 1 /14 How Brexit will affect your travel to Europe How Brexit will affect your travel to Europe Passports British passports that expire after 29 March 2019 will continue to be valid as UK travel documents, but will lose the power that comes with being a European Union passport – notably the right of free movement within the EU27. UK passports issued from 30 March 2019 will have the words “European Union” removed from the cover and the first page (along with the translations into Welsh and Gaelic). But they will still be burgundy. By October 2019, new British passports will have dark blue covers Getty How Brexit will affect your travel to Europe Pets You will still be able to travel to the EU with your pet after Brexit, but it could well get more complicated depending on the status that the European Union decide to apply. If the UK is given “Part 2 listed status”, there would be some extra requirements for travelling pets and owners post-Brexit. “These would require an additional visit to the vet and some additional papers to be carried but would not prevent you from enjoying your trip,” says Eurotunnel. But it adds that if the UK is given unlisted, third-country status, “owners who wish to travel with their pets from the UK to EU nations will need to discuss their specific preparations and requirements with an Official Veterinarian at least four months prior to their desired travel date AFP/Getty How Brexit will affect your travel to Europe Eurotunnel/Eurostar The Treaty of Canterbury between the UK and France governs the Channel Tunnel link and operations will continue – subject to any local disruption at Folkestone and/or Calais AFP/Getty How Brexit will affect your travel to Europe Driving Motorists, whether taking their own cars or hiring abroad, are likely to need to obtain an International Driving Permit or two; different EU countries are signed up to different treaties, so for a trip embracing Spain and France you would need both types. These are currently sold from a limited number of Post Offices, but the government intends to make them widely available. The cost is £5.50 for each. Motor insurance will no longer automatically extend to the EU. Insurers will provide on request a “Green Card”, for which an extra charge will be made PA How Brexit will affect your travel to Europe Flights Even in the event of a no-deal Brexit, flights will continue to operate between the UK and European Union. However, in the event of the UK leaving with no deal, many flights are likely to be cancelled because departures would be capped at 2018 levels. As UK airlines have already announced thousands of new flights to Europe from the end of March 2019, some would have to be cancelled Getty How Brexit will affect your travel to Europe Air routes The network of flight links between Britain and eastern Europe could be affected by any reduction in the number of workers from those countries. Not only do they use the flights – so do their families and friends PA How Brexit will affect your travel to Europe Flight disruption rights Current European passengers’ rights rules, known as EC261/2004, stipulate high payouts for delays and cancellations that cannot be attributed to “extraordinary circumstances”. Buried in a document called Beyond the Horizon: The Future of UK Aviation, the government says “the UK will not fall below current standards of protection when we leave the EU” AFP/Getty How Brexit will affect your travel to Europe Entry regulations to the European Union From 11pm GMT on 29 March 2019, UK travellers will become “third-country nationals” when travelling to Schengen countries and subject to the standard rules of admission for citizens of nations such as the US, Japan and Australia. That means there must be at least 90 days (roughly three months) left on your passport beyond your intended date of departure. Because third-country nationals can remain in the Schengen area for 90 days, the actual check carried out could be that the passport has at least six months’ validity remaining on the date of arrival Getty How Brexit will affect your travel to Europe Online registration prior to travel – ETIAS From 2021, non-EU nationals who do not require a visa to enter the Schengen area – including British travellers – will need to request prior authorisation to visit Schengen countries. The Travel Information and Authorisation System (ETIAS) is aimed at reducing the “migration, security or public-health risk” from nationals of visa-exempt third countries, which is what the UK will become after Brexit. It costs €7 for three years AFP/Getty How Brexit will affect your travel to Europe ‘Brexit clauses’ A large number of travel providers – even including National Express coaches – have added “Brexit clauses” to their terms and conditions. These generally specify that they will not be liable for “consequential losses” as a result of Brexit-related issues PA How Brexit will affect your travel to Europe ‘Fast track’ lanes for passport control entering EU countries British passport holders will not be able to use them, and must join the queue for third-country nationals. People holding an EU passport or ID card as well as a British passport will be able to exit the UK on the British passport but enter Europe on the EU document Getty How Brexit will affect your travel to Europe Ferries The ferry industry insists vessels will continue to sail. The UK Chamber of Shipping says: “Unlike the carriage of cargo, trade deals do not have a significant effect on the cruise and passenger ferry industry. The explicit standardisation of commodity codes and tariffs associated with trade deals have little relevance to holidaymakers.” Having said that, the government and Kent County Council are planning for possible chaos at Channel ports because of a backlog of trucks in the event of a no-deal Brexit. This would impinge on holidaymakers’ plans PA How Brexit will affect your travel to Europe European Health Insurance Card (EHIC) The EU says: “If you fall ill or have an accident during a visit to another EU country, as an EU citizen you have the right to receive the necessary public healthcare in any EU country under the same conditions as people in the host country.” The EHIC also works in Iceland, Norway, Switzerland and Liechtenstein. Treatment, says the NHS, is “at a reduced cost or, in many cases, free of charge”. From 11pm GMT on 29 March 2019, when the UK ceases to belong to the European Union, British travellers will have no automatic right to use the EHIC. There is no certainty about what may replace it PA How Brexit will affect your travel to Europe Mobile phones From 30 March 2019, the law banning mobile phone firms from charging extra for calls and data in Europe will cease, though operators have yet to set out exactly what will replace it. In theory, mobile phone firms can impose whatever fees they think the market will bear. But Dave Dyson, chef executive of Three, says his firm is “committed to maintain the availability of roaming in the EU at no additional cost following Brexit” AFP/Getty

And MPs will vote again on the crisis just one week later, a concession forced by the threat of cabinet resignations over the growing risk of a no-deal Brexit.

Until her visit to Belfast, Ms May had insisted three options were being considered for reworking the backstop – a time limit, an exit mechanism, or ill-defined “alternative arrangements”.

However, she appeared discomforted by questions from local business leaders and journalists, in the part of the UK where the guarantee – to avoid the return of border points and checks – enjoys strong support.

Asked how she could win support for a deal stripped of the backstop, Ms May replied: “I’m not proposing to persuade people to accept a deal that doesn’t contain that insurance policy for the future.

“What parliament has said is that they believe there should changes made to the backstop.”

Told that some in Northern Ireland believed she had “shafted them”, she said again: “There is no suggestion that we are not going to ensure that, in the future, there is provision for this – it’s been called an insurance policy, the backstop.”

However, the Brady amendment – passed by the Commons last week in a rare show of Tory unity – “requires the Northern Ireland backstop to be replaced with alternative arrangements to avoid a hard border”.

Furthermore, the working group of pro- and anti-EU Tories, under the so-called “Malthouse compromise”, is still exploring those alternatives, with civil service support.

Downing Street tried to repair the damage, insisting all options remained open, including full replacement of the backstop.

But Guto Bebb, a Conservative supporter of the People’s Vote campaign, said Ms May’s comments proved “there won’t be any substantial changes to her Brexit deal”.

“Instead, she’s going through the motions with the EU, letting the clock tick down further, and then will try again to force through her deal that doesn’t command the support of parliament, doesn’t command the support of the public, and is a bad deal for the future of our country,” he said.

The prime minister will meet both Jean-Claude Juncker and Donald Tusk, the presidents of the European Commission and Council respectively, on Thursday.

Earlier at cabinet, former pro-Remain ministers pushing for an extension to the Article 50 process, if necessary to prevent a crash-out, stayed silent as the prime minister insisted Brexit must still happen on 29 March.