Britain’s departure from the EU should lead to a border poll on a United Ireland, deputy first minister of Northern Ireland, Martin McGuinness, has said.

The former IRA chief-of-staff said that if Britain voted to leave the EU then there was a “democratic imperative” to allow people on the island of Ireland to vote on reunification.

“If Britain votes to leave the European Union then that could have huge implications for the entire island of Ireland and, given all the predictions, would run counter to the democratic wishes of the Irish people,” the Sinn Féin leader said.

McGuinness said the electorate should have the right to vote to “retain a role in the EU.”

The largest unionist force in Northern Ireland, the Democratic Unionist party, is backing the campaign to leave the EU. However, the Ulster Unionist party’s ruling executive voted last week to support David Cameron’s calls for a vote to remain in the EU in the June referendum.

Northern Ireland secretary Theresa Villiers has joined the campaign in favour of leaving the EU.

A border poll is highly unlikely to be granted by London even if the UK leaves the EU after the referendum. Yet even if one was held, successive opinion polls in Northern Ireland have shown a substantial majority in the region favour remaining within the UK.

Dissident republican critics of Martin McGuinness have pointed out that any border poll would only be held within the confines of Northern Ireland, which they regard as an “artificial” or “partitionist” entity created out of the 1921 Anglo-Irish Treaty.

The dissidents and in particular the 1916 Societies have launched an island wide petition demanding that any border poll be held in both the Republic and Northern Ireland.

This runs counter to the key principles within the 1998 Good Friday Agreement, an internationally recognised treaty that ensures any vote on constitutional change is only held within Northern Ireland.