The European Union has been accused of behaving dishonourably in the Brexit negotiations by seeking to use the Irish border issue to lock the UK into the bloc's laws.

Dominic Raab said it was time for Britain to "stand up" to the EU, as he warned a delay to the UK's withdrawal would reduce the chance of securing a deal.

Britain is due to leave the EU at the end of this month, but Prime Minister Theresa May this week offered MPs the chance to vote to seek an extension to Article 50 to delay its departure if her deal is defeated and a no-deal Brexit is rejected.

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The former Brexit secretary also suggested a softening of the approach among Eurosceptic Tories over the controversial Irish backstop to prevent a hard border, by saying the "technical device" for making the changes they require was "second order".

Referencing the resignation of agriculture minister George Eustice on Thursday, he told BBC Radio 4's Today programme: "(Mr Eustice) referred to frankly the dishonourable way that they've tried to bully us and shove us around and it's time for us to stand up as a Government and as a country.

"It's very clear that they've used the Northern Ireland protocol and backstop as a means of trying to press on the sensitive issue of Northern Ireland and with all the sensitivities around that, in order effectively to try and lock us into a range of their laws, really just to undercut our competitive market."

Mr Raab said he had "no problem" with the EU negotiating to protect their interests, and said the Prime Minister had "bent over backwards" to try and "satisfy and respect the equities on the EU side".

"But I think trying to use Northern Ireland - given the history of that conflict, given the secessionist tendencies in other European countries - in order to put pressure on us in the way that they have, no, I don't think that's right.

"Frankly I don't think it's right from the point of view of European unity and solidarity."

Mr Raab restated his opposition to Theresa May's withdrawal deal, over which he resigned in November, and called for substantial and substantive changes to it.

But in an apparent softening, the MP said: "We're not being dogmatic on this on the Brexiteer side - we want to see the substance of it change, but the vehicle, the technical device for doing it, is second order.

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"What matters is that we can exit that backstop."

Mr Raab also warned that a delay to Brexit would "weaken" Britain's leverage in the negotiations, and said: "The chances of a deal get that bit slimmer because they are less likely to compromise.

"I'm strongly against any delay, and I think from the EU's point of view it signals to them that actually their intransigence pays off and that's the wrong message for the UK to be sending to Brussels at this moment."

But Mr Raab said he was "open minded" about a short delay of a couple of weeks to get the necessary legislation through.

The former Cabinet minister expressed his support for Mr Eustice over his decision to quit the Government over Brexit.

Mr Eustice said he wanted to return to the backbenches "to be free to participate in the critical debate that will take place in the weeks ahead".