Alex Salmond has promised 'some revelations' from behind the scenes about working with successive UK Governments led by Tony Blair, Gordon Brown and David Cameron when he appears before MPs this week.

The former First Minister has been called to give evidence to the House of Commons' Scottish Affairs Select Committee which has launched an inquiry on intergovernmental relations between London and Edinburgh in the 25 years of devolution.

"I will give them some revelations, why not?" he told The Herald on Sunday.

Mr Salmond, who was First Minister from 2007 to 2014, will be in front of the committee on Tuesday after a session tomorrow hears from former UK Scottish Secretaries Douglas Alexander, Desmond Browne and Helen Liddell.

Ahead of his appearance at the Committee, Mr Salmond revealed that the worst relationship he had with any Prime Minister was with Tony Blair but added that his relationship with the then Labour Government improved when Gordon Brown became Prime Minister. He pointed out the two men worked together to save the Grangemouth Oil Refinery. The facility is currently facing closure.

The Herald: Alex Salmond and David Cameron signing the Edinburgh Agreement in 2012Former First Minister Alex Salmond and Former Prime Minister sign the Edinburgh Agreement in 2012 which set the terms for the 2014 independence referendum.

Mr Salmond went on to say that the best working relationship between the UK and Scottish Governments - perhaps surprisingly - was with David Cameron, now Lord Cameron the Foreign Secretary, in the three years up to the independence referendum in 2014.

"Tony Blair was Prime Minister when I became First Minister and at that point relationships were disastrous. Blair didn't even phone me or have any contact with me when I began First Minister in 2007, and in fact we never spoke during the time he was Prime Minister and I was First Minister," Mr Salmond, who now leads the Alba Party, told The Herald on Sunday.

"I'll probably go into this in graphic detail when I speak to the committee but I think at the time Blair was busy arranging the release of Mr Megrahi with Colonel Gaddafi - and BP oil licences."

The Herald: Former Prime Minister Tony Blair did not phone Alex Salmond when Mr Salmond became First Minister of Scotland after the SNP ousted Labour from power in Holyrood in 2007. Photo PA.

He added: "But he had also blotted his copy book. The (Holyrood 2007) election was the only election he ever lost. I think he was upset. But he never once phoned me. A totally graceless individual. I suppose it was towards the end of his term and he had given up on the courtesies and niceties and he just thought 'I'm not phoning that person. Things improved when Gordon Brown became Prime Minister.

"Even though Gordon and I didn't see eye to eye on lots of different things there was a natural courtesy which you would extend.

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"I phoned him when he became Prime Minister and he phoned me when I became First Minister. Relationships weren't easy though they improved in 2008 when we saved Grangemouth Oil Refinery by a joint initiative. And after we were both able to bask in the good publicity of saving the refinery things improved a bit."

He added: "The best working relations [between the UK and Scottish Government] during my period as First Minister was from 2011 and 2014.

"I think then everyone in both governments were on their best behaviour. The date and process had been set for the referendum and it was not in the interests of Westminster to act in an aggressive or bullying manner as it would have counted against them.

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"So they were on their marks to try and demonstrate how amenable, conciliatory and supportive they were. Similarly it wasn't in the interests of the Scottish Government to act in an obstreperous manner."

The Herald: Alex Salmond said he had a better working relationship as FM with former PM Gordon Brown than with Tony Blair. Photo PA.

He added: "I think because the date and process for the referendum had been set that made negotiations on other things much easier than they had previously been - and also much much better than relationships are now."

Mr Salmond also told The Herald on Sunday that during Mr Cameron's career in Downing Street when the Conservatives were in a coalition with the Lib Dems, he as First Minister helped broke better engagement between the UK and China.

He compared the episode, which he believed illustrated a spirit of co operation, with a more fractious relationship currently where First Minister Humza Yousaf is not allowed to meet foreign leaders without a UK official present.

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The former First Minister said the rapprochement with China followed a friendship he struck with former Chinese premier Li Keqiang following his visit to Scotland in 2011.

"I was always meeting foreign leaders and I will tell the committee on Tuesday that it was far from being seen as a problem," he said.

He said in 2011 the UK Government found itself "in the doghouse" with China because Mr Cameron and Deputy Prime Minister Nick Clegg "had upset" the Chinese Government.

The UK Government, he said, were keen to rebuild the relationship and the then UK Ambassador to China turned to Mr Salmond for help when both men were in Beijing later in 2011.

"I had become friendly with Li Keqiang who was then second in command in China. The Ambassador asked me to help him get into the [Chinese] leadership compound which I was happy to do," he said.

He said it was a sign of how badly the relationship between the two governments had got that UK ministers now required the First Minister to be "chaperoned" when meeting overseas leaders.

"The idea that David Cameron would have tried to have me chaperoned at meetings is so off the wall it is ridiculous," said Mr Salmond.

"They are throwing their weight around as they have got the Scottish Parliament in a box. The idea that Humza should be accompanied by a British Government official whenever he meets a foreign leader is absurd."

The House of Commons' cross-party Scottish Affairs's Select Committee of MPs is examining how relations between Westminster and Holyrood have evolved in the 25 years since devolution, and how they compare with expectations in 1998. 

The first session this week will take place on Monday afternoon with MPs set to question  Desmond Browne and Helen Liddell about their reflections on intergovernmental relations during their periods in office.

Whitehall’s approach towards devolved institutions and how the election of an SNP-led Scottish Government in 2007 affected relations between the two Governments are likely topics for discussion.

Mr Salmond will appear as a witness at the second session this week on Tuesday with questions likely on his experience of how effectively formal intergovernmental structures mitigated conflict between the two governments, and how political events such as the 2014 independence referendum affected relations.

The Committee has also confirmed that former First Minister Nicola Sturgeon is due to appear before the Committee on April 29 to discuss her experience of intergovernmental relations during her time in office.

In previous sessions, the Committee heard evidence from former UK Government ministers and officials and leading academics for their expert views on the inter-governmental framework. The Committee launched its inquiry in July last year.