BRITAIN has decided to "tear up" the Good Friday Agreement by pressing ahead with Brexit, former taoiseach John Bruton has said.
The one-time Fine Gael leader said the outcome of the Brexit vote had "negated" the 1998 referendum held on both sides of the border, which showed a majority in favour of the peace agreement.
He said a no deal would lead to a hard border.
"There will be a hard border if there is no agreement – that's clear under EU law if you look at the paper that was produced last month by the European Commission," he said.
"It's quite clear that there will have to be control on the EU's borders and one of those EU borders in the event that Britain leaves the EU will be in Ireland."
He said the Republic had also changed its constitution as a result of the referendum but that Britain "comes along unilaterally and essentially decides to tear that up" in its pursuit of Brexit.
"And that's why we have insisted on a backstop to protect the Good Friday Agreement, so that Britain can't do that," he said.
The former taoiseach also described Sinn Féin's abstentionist policy as a "tragedy".
He said the voice of Irish nationalism was missing in the debate over the UK's withdrawal from the EU.
Mr Bruton, who served as taoiseach from 1994 to 1997, told BBC Radio 4's Today programme: "I think the record of Sinn Féin MPs not taking their seats in parliament has been extremely bad.
"Ireland was partitioned in 1920 when Sinn Féin refused to take their seats after the 1918 election."
