The British Prime Minister says internal border checks may be needed within the UK, if it votes to leave the European Union.
David Cameron was speaking in the House of Commons with one week to go before polling in the Brexit referendum.
The Prime Minister has pulled out of an event in Manchester on Friday where he was due to share a stage with Enda Kenny.
It has been claimed that a Brexit could have serious implications for Donegal with border checkpoints inevitable.
He was asked today if there was any way for border controls between the Republic and the North to be avoided: