Minister for Foreign Affairs Charlie Flanagan has urged Irish people living in Britain to join the campaign to keep the United Kingdom in the European Union.

Speaking in London after meetings with British foreign secretary Philip Hammond, Labour MPs and Irish business and community groups, Mr Flanagan said the Government had a "clear message" for the hundreds of thousands of Irish citizens entitled to vote in the referendum on June 23rd.

“I would strongly encourage Irish communities to become very much involved in this campaign,” he told The Irish Times.

"I believe it's in the best interest of the relationship between Ireland and Britain, but I also believe that it's in the positive interest of the European Union that we have a strong UK as members of the European Union.

“Of course, I fully accept the sovereign right of the people of the United Kingdom to make this decision themselves,” Mr Flanagan said.

“But I believe that I have an obligation as a neighbouring foreign minister with a strong stake here in terms of the Irish community.”

Some 430,000 people living in Britain were born in Ireland, according to 2011 census figures, and Irish citizens of voting age who are resident in Britain are entitled to vote in the referendum.

Last month saw the launch of Irish4Europe, a group that hopes to mobilise Irish voters in favour of Britain staying in the EU.

Later this month, the British Irish Chamber of Commerce will host a pro-EU event in London, which acting Taoiseach Enda Kenny and British prime minister David Cameron are expected to attend.

“Over the next weeks and months you will see a mobilisation of support on the part of the many Irish community groups and the many business and commercial groups,” Mr Flanagan said.

“And there will be a series of events which will act to mobilise the Irish community.

"And not only here in London but also in the regions, cities like Liverpool, Manchester and the northeast, where there are strong and active Irish communities, many of whom have been politically motivated over a long number of years by various campaigns."

Polls

With opinion polls showing the referendum on a knife edge, voter turnout could hold the key to victory for either side.

Mr Flanagan said that Irish cultural and sporting organisations in Britain could play a crucial role in mobilising voters to back remaining in the European Union.

Irish4Europe has made clear that it is not seeking any financial support from the Government, and Mr Flanagan said he did not envisage “expending money directly” on the Remain campaign.