The UK does not have to have identical laws to Brussels in order to align regulations to allow free-flowing trade, one of the cabinet’s leading Brexiters, Chris Grayling, has said, hinting at the path the government may pursue to break the stalemate over the Irish border.

Michel Barnier, the EU’s chief Brexit negotiator, has told member states that the British government has less than 48 hours to agree a text on a potential deal or negotiations will not move on to the second stage.

Downing Street needs to agree a solution over the Irish-Northern Irish border that will satisfy both the Irish government and Theresa May’s parliamentary allies, the Democratic Unionist party.

The negotiations centre on a guarantee of “regulatory alignment” of Northern Ireland with the EU, to allow a free flow of trade and prevent a hard border, which the DUP said was unacceptable if it put Northern Ireland on a different footing to the rest of the UK.

Q&A What is regulatory alignment? Show Hide Inside the EU, both Ireland and Northern Ireland (as part of the UK) are part of the single market and customs union so share the same regulations and standards. The only way to avoid a hardening of the border after Brexit is to ensure regulations and standards on both sides remain more or less the same in areas like food, medicines and so on. This might imply a permanent acceptance of EU rules – something that would be anathema to hardline UK Brexiters and the DUP, who reject anything that would "decouple" the North from the UK. David Davis told parliament that regulatory alignment would not mean adopting exactly the same rules as the EU but "mutually recognised" rules and inspections. However, an official in Brussels countered that regulatory alignment would mean that the UK would have to implement rules from Brussels without having any influence over them. What is the government’s plan for ‘regulatory alignment’?

Davis says the UK could continue to follow some rules of the EU’s single market. This would help avoid a hard border, but would also limit the UK’s ability to diverge from EU regulations. What does the EU think?

Davis thinks the UK and EU can agree to meet the same aims, while achieving them in different ways. The EU believes this could see its standards on workers’ rights and the environment undercut. Can it even work?

Parliament cannot bind its successors. This principle would mean a deal would never be completely secure for more than five years – putting its feasibility in doubt. Photograph: PA

Grayling, the transport secretary, said such alignment did not mean the UK had to accept all Brussels regulation. “Plenty of countries have what you call regulatory equivalence where in one country you have anti-money laundering law and you have another in another country,” he told BBC Radio 4’s Today programme.

“They are not the same, they have a similar goal and each recognises the integrity of the other to stamp out money laundering.”

Grayling said the government would not stitch up a deal where UK laws had to match those of the EU. “We don’t have to have, and we’ve never said we will, and we don’t want to have a situation where in future our laws are identical to the European Union,” he said.

“There will be areas where we do do things in a similar way. There will be areas where we don’t do things in a similar way. That’s all the prime minister was seeking to achieve to make sure we can ensure trade flows as freely as possible across the borders.”

Overnight, the Irish prime minister, Leo Varadkar, struck a similar note, saying that regulatory alignment did not have to apply to everything, merely areas of “north-south” activity.

However, it is understood the DUP believes No 10 is still not offering adequate guarantees that Northern Ireland will be treated in exactly the same way as the rest of the UK after Brexit.

Quick guide Why is the Irish border a stumbling block for Brexit? Show Hide Counties and customs Inside the EU, both Ireland and Northern Ireland are part of the single market and customs union so share the same regulations and standards, allowing a soft or invisible border between the two.

Britain’s exit from the EU – taking Northern Ireland with it – risks a return to a hard or policed border. The only way to avoid this post-Brexit is for regulations on both sides to remain more or less the same in key areas including food, animal welfare, medicines and product safety. The 'backstop' in Theresa May's Withdrawal Agreement was intended to address this - stating that if no future trade agreement could be reached between the EU and the UK, then rules and regulations would stay as they are. This has been rejected by Brexit supporters as a 'trap' to keep the UK in the EU's customs union, which would prevent the UK striking its own independent trade deals. There are an estimated 72m road vehicle crossings a year between Northern Ireland and the Republic of Ireland, and about 14% of those crossings are consignments of goods, some of which may cross the border several times before they reach a consumer. Brexit supporters say this can be managed by doing checks on goods away from the border, but critics say it will be difficult to police this without any physical infrastructure like border posts or cameras, which could raise tensions in the divided communities of Ireland.

Interactive: A typical hour in the life of the Irish border Photograph: Design Pics Inc/Design Pics RF

Grayling said such disputes were to be expected at tense stages of negotiations. “This is a complex negotiation running up to a deadline next week. It’s not surprising at this stage in the negotiation.”

For the DUP, the border question is raw identity politics | Graham Gudgin Read more

Meanwhile, the Brexit-backing Conservative MP Bernard Jenkin said the UK must not give up its goal of “regulatory autonomy” after Brexit, and accused the European commission of using the Republic of Ireland as a “proxy” to prevent the creation of an open frontier on the EU’s border.

“I don’t think we should walk away, but I do think we should take a firm line, as the prime minister did earlier this week,” Jenkin told BBC Radio 4’s Today programme.

“We shouldn’t be allowing ourselves to be bullied into promising more and more money, or giving up the goal of regulatory autonomy, or being dragged into a long period of uncertainty without clarity on what we are getting at the end of it.”