MARTIN McGuinness was drafted in to calm down a blazing row at a recent meeting between the Scottish and UK Governments over Brexit, a former Northern Ireland first minister has claimed.

Lord David Trimble said the dispute between Edinburgh and London was sparked during a session of the joint ministerial council, the forum set up to get input from the devolved administrations over the process of leaving the European Union.

The Nobel Peace Prize winner said that as the meeting descended into "a lot of shouting, a lot of bad blood", representatives from Westminster called McGuinness to step in.

Trimble was leader of the then-largest party in Northern Ireland, the Ulster Unionists, in the first power-sharing government in 1998, months after the Good Friday agreement.

He said: “I heard recently from a very senior government minister in Downing Street that they had to call in McGuinness last year to act as a peacemaker between London and the Scots Nats!

"On the joint ministerial council between the devolved governments of Edinburgh, Cardiff and Belfast, in co-operation with the national government in London, there was a lot of shouting, a lot of bad blood."

Trimble added that McGuinness was "calm and rational" and "helped turn down the temperature at that meeting".

His claims follow a growing number of reports suggesting that relations between Edinburgh and London are poor.

Scottish Brexit Minister Mike Russell took to social media on Monday to say he had not been given official notification of the date - March 29 - on which the Prime Minister will trigger Article 50and and was left to hear it on the BBC news.

There is also considerable upset in Edinburgh that May did not formally respond to the Scottish Government's Scotland in Europe proposals, published in December. The plans would have allowed Scotland to remain in the European single market while staying a part of the UK.

A spokesan for First Minister Nicola Sturgeon dismissed Trimble's claims, saying: “This suggestion is complete and utter nonsense – it is a fantasy concoction of events which simply didn’t take place, from someone who wasn’t present at any of the meetings the claims are based on.”

Meanwhile, following McGuinness's death yesterday it emerged that Trimble had written to him after learning of his illness to tell him of his appreciation for his peace process work and how many would feel "greater optimism" if he was "at the helm" in the current political crisis.

In the letter, Trimble spoke of his "appreciation" of the Sinn Fein veteran's work in bringing devolution to the Northern Ireland Assembly.

He said: "On reflection, I thought it behoved me as the first minister when we first achieved devolution to the Assembly created by the Good Friday Agreement some 18 years ago, to say how much we appreciated all that you did to make that happen.

"In doing that you reached out to the Unionist community in a way some of them would have been reluctant to reach out to you.

"Without knowing the detail of how the republican movement got to that point, I and my colleagues believed that you were indispensable."

The NI Assembly was today holding a special session to pay tribute to McGuinness.

The speaker invited members to gather at midday in honour of the former IRA leader turned peacemaker.

The Sinn Féin politician died early yesterday in a Derry hospital with his family by his side. He was 66 and had been suffering from a rare heart condition. His funeral is to take place in his native Derry tomorrow.

In his letter dated March 12, Trimble praised the former deputy first minister's "even-tempered manner" which was "never at the expense of your principles".

He wrote: "Perhaps the best expression of your approach was your meeting with Queen Elizabeth".

"There are many today, as we sit with the clock ticking down to the deadline for getting the institutions up and running again, who think that if you were at the helm, we would face this prospect with greater optimism."