More voters in Britain rate leaving the European Union as a priority ahead of maintaining the Union with Northern Ireland, a poll has suggested.

More than a third of those polled (36%) said exiting the European Union was a higher priority than keeping Northern Ireland within the UK.

Of those surveyed, 29% said retaining Northern Ireland within the UK was more important than Brexit.

Around 22% said neither was important, while the remainder said they did not know which one to prioritise higher.

The YouGov poll, commissioned by radio station LBC, did not survey voters in Northern Ireland. The online poll sampled 1,630 adults living in Britain. It was conducted between 21 and 22 March.

DUP MP Jeffrey Donaldson told LBC he did not think the survey findings were relevant.

"The Good Friday Agreement states very clearly that the principle of consent means that it's for the people of Northern Ireland alone to decide whether we remain part of the United Kingdom," he said.

"Since the UK government, the Irish government and Brussels have all said that any Brexit agreement must fully recognise all of the terms of the Good Friday Agreement, I really don't think this is relevant."

Sinn Féin leader Mary Lou McDonald said she was "not hugely surprised" by the poll result.

"Ultimately the people who care about Ireland north and south are the people who live on this island and people on our neighbouring island evaluate things in a totally different way and they look to their own future as they understand it," she said.

She added: "If the people of Britain are minded to break the union and say a fond farewell and to facilitate the reunification of our country we would greet that news with delight, to put it mildly."

Meanwhile, the issue of the border on the island of Ireland needs to be resolved by June at the latest, according to the Sinn Féin leader.

Ms McDonald accused the British government of "bluster and procrastination" on the issue.

Speaking in Belfast, Ms McDonald said that concrete proposals are needed on how the British government intends to avoid a hard border.

"The reality is we should at this stage have seen some concrete proposal from the British government," she said.

"The idea of pushing this out to October is absolutely unacceptable."

"They need to understand that further delay is not acceptable, they need to show us the colour of their money, they need to put forward a concrete proposition and proposal as to how Ireland is protected, how the north of Ireland is protected, how our peace agreements are protected, how our economy is protected." 

Yesterday the British Labour Party indicated it is preparing to forge a cross-party alliance to guarantee there will be no infrastructure on the border between Ireland and the UK after Brexit.