Last night Mr Straw was accused of an act of “desperation to avoid political embarrassment”. The claim came as well-placed sources told The Herald heated arguments occurred between the late Donald Dewar and Ron Davies in one corner, and John Prescott and the Justice Secretary in the other, over detailed policy going down to issues such as devolution of the Potato Marketing Board.

It is also thought some of the rows concerned the so-called “tartan tax” and how many powers should be devolved to the Welsh Assembly in light of Holyrood’s proposed ability to make laws.

At the time, Mr Dewar and Mr Davies were the respective Scottish and Welsh Secretaries while Mr Prescott was Deputy Prime Minister, responsible for the English regions, and Mr Straw was Home Secretary, overseeing constitutional matters.

One senior Whitehall source recalled Mr Dewar returning to the Scotland Office, recounting “really tough arguments”. He said: “Jack was putting up a tough battle. He was very scrupulous and there was a lot of fine detail down to where the Potato Marketing Board would go. He would argue over all the fine print.” The source added: “It ended with the result the Bill was stronger and basically anything that wasn’t specifically reserved was devolved.”

Alan Trench, a constitutional expert at University College London, said: “It’s clear from the research I’ve done that there were some serious disagreements about various aspects of devolution at that time.

“The Secretaries of State for Wales and Scotland were seeking to get all they possibly could and were facing a number of rearguard actions from the likes of Straw and Prescott.”

In a written statement, the Justice Secretary said he was using his veto on disclosure of the Cabinet’s devolution talks for only the second time after Christopher Graham, the Information Commissioner, allowed the move following a Freedom of Information request; the first time was a block on Cabinet discussions over the Iraq war.

Mr Straw explained this was an “exceptional” case and recognised a “competing public interest” between disclosure and confidentiality.

He referred to how “robust debate” was central to Cabinet decision-making, which depended on a “high level of confidentiality”. In this case, disclosure would have “run the risk of an adverse effect on officials’ and ministers’ ability to conduct rigorous and candid risk assessments of their policies and programmes”. It was not in the public interest for this to happen, he argued.

Mr Straw referred to the disclosure of “individual and divergent ministerial views”, that would have meant the UK Government would have been “unable convincingly to put forward the collective decision for which all Government ministers are accountable”.

Committee minutes contained instances of “different views” being expressed by identified ministers as well as when they were unable to “come to an agreed position”.

He stressed that, although the issues were discussed in 1997, they were still “live” in 2005 when the FoI request was made.

The Justice Secretary also pointed out that, in 2005, of the 23 original members on the Cabinet Ministerial Committee on Devolution to Scotland, Wales and the English Regions, 15 were still Government ministers. At the present time, seven still remained so.

However, Mr Graham said he was “concerned” the Government might now “routinely use” the veto.

The commissioner also ticked off Mr Straw for blocking disclosure just weeks before the matter was due to go before the Information Tribunal in January. He said he “regrets the tribunal’s role has been disregarded at this stage”, noting how this had not been the case in relation to Cabinet minutes on Iraq when his decision was upheld on appeal.

Mr Graham confirmed he would now send a report to MPs on the matter.

Last night, David Howarth, the LibDem justice spokesman , said Mr Straw’s decision undermined Labour’s claim to open government, noting: “Ministers are losing their sense of proportion in their desperation to avoid political embarrassment.”

Pete Wishart for the SNP branded the veto a retrograde step, which raised “serious questions about what Labour has to hide”.