Tanaiste Simon Coveney has become embroiled in a bizarre war of words with former UK Foreign Secretary Boris Johnson over whose idea it was to build a bridge between Scotland and Northern Ireland.

Speaking ahead of a major business and leadership summit in Dublin this week, Mr Johnson exclusively told the Sunday Independent the Tanaiste came to him with the idea of building a 35km-bridge across the Irish Sea.

The Conservative Party member said Mr Coveney's proposal for a bridge was "brave and right" and should be "seriously examined".

"When I was foreign secretary, my Irish counterpart Simon Coveney came into my office and said 'let's build a bridge' - and he wasn't being metaphorical. He was entirely serious," Mr Johnson said.

Yesterday, Mr Coveney dismissed the claim and insisted he was focused on Brexit negotiations.

"There are 82 days to go to Brexit and we would not allow ourselves get distracted by a bridge," he told the Sunday Independent.

"In all my interactions with Boris I have made clear that protecting peace in Ireland and preventing a hard Border is my priority," he added.

The Tanaiste said a "physical bridge is an engineering challenge for the future" and insisted he was focused on protecting the Good Friday Agreement.

A source close to the Tanaiste said Mr Johnson's version of events was "complete nonsense".

The source said the only time a bridge was discussed in negotiations with Mr Johnson was when the then UK foreign secretary mentioned it in passing prior to a meeting with Mr Coveney in Dublin.

Mr Johnson has spoken several times in favour of building a €17bn bridge from Portpatrick, Scotland, to Larne or Bangor, Northern Ireland.

In comments ahead of his highly anticipated appearance at the Pendulum Summit in Dublin's Convention Centre, Mr Johnson said: "The friendship and partnership between the UK and Ireland is so huge - and growing - that the day is surely coming when we should build a fixed link of some kind."

He said in the UK they buy "prodigious quantities of Irish drink" and eat "vast quantities of Irish cheddar cheese" while also depending on "Irish talent in every walk of British life".

"If we get Brexit right then I have no doubt that we can not only protect that trade but watch it grow at pace," he added.

Mr Johnson will be interviewed by RTE broadcaster Bryan Dobson at the Pendulum Summit on Thursday.

Other speakers include actors John Cleese and Colin Farrell, along with comedian Ruby Wax, business coach John Mattone and Leinster coach Stuart Lancaster.