The Rolls-Royce civil servant who stuck to the beaten track

Lord Butler of Brockwell lived up to his reputation yesterday as a brilliant exponent of Whitehall doublespeak. As Sir Robin Butler, he once famously told the Scott inquiry into the Iraq supergun affair: "You have to be selective about the facts. It does not follow that you mislead people. You just do not give the full information ... It was a half answer. Half the picture can be true."

Yesterday, the former cabinet secretary gave a bravura performance at the press conference in Whitehall to launch his report, while the other members of his committee sat watching mutely.

His report identified a host of mistakes over the intelligence failures that paved the way for Britain to go to war against Iraq. But ultimately his report blamed no one. It was only when The Independent asked Lord Inge, the former chief of the defence staff, for his personal view of the politicisation of the intelligence services, that cracks started to appear in the smooth Butler presentation.

Lord Inge made it clear that, although he had signed up to Lord Butler's conclusions, there had been splits in his committee behind the scenes about the language of the report. Where Lord Butler calmly repeated that there was no evidence of the Joint Intelligence Committee, headed by John Scarlett, being "distorted" by their political masters, Lord Inge said: "It was asked to do things which I personally don't think it should do, in the sense that intelligence and public relations need to be kept separate."

Lord Butler is regarded as a Rolls-Royce civil servant, who prefers to ride a bicycle around Whitehall. Yesterday, he took the number 24 bus for the mile journey from his flat in a mansion block near Westminster to the Whitehall office where he has spent the past weeks with his team, interviewing senior ministers, including Tony Blair, spy chiefs, and Downing Street officials.

Wearing a stone-coloured raincoat, the thin, 66-year-old with flying white hair walked briskly into the Cabinet Office unnoticed by the press photographers and the Sky TV crew awaiting his arrival. An official said: "They thought he was going to arrive in a car. They just didn't recognise him."

Inside the Cabinet Office, he joked to his committee and their officials: "My ego has been severely dented." But his anonymous appearance belied the skill with which he produced the report. One source close to the committee said it was "all there if you look closely - it has a slow-burning fuse".

If the Butler report eventually goes off under Mr Blair, do not expect its author to turn a hair. In the early morning of 12 October 1984, he was working on private papers with Margaret Thatcher when an IRA bomb with a timer device exploded in a bathroom above her suite at the Grand Hotel, Brighton. It was intended to assassinate her and half of the Cabinet, and would have succeeded but for a fluke in the building's construction which diverted tons of masonry down the staircase.

Lord Butler, who served five prime ministers, from Edward Heath to Mr Blair, narrowly escaped death that morning. He did so again in 1991 when he was with John Major as the IRA launched a mortar attack on Downing Street from a van in Whitehall, sending most of the Cabinet diving for cover under the cabinet table.

Born in the genteel resort of Lytham St Anne's, at the posh end of the coast near Blackpool, Frederick Edward Robin Butler - later known as Ferb - was sent by his father, the managing director of a paint manufacturing firm, to Harrow school. He went on to University College, Oxford, where he took a double first and won two rugby blues as a wing forward, fast and strong. He came top in the civil service entrance exam and raced through the ranks after joining the Treasury in 1961. He became private secretary to Mr Heath in 1972, at the age of 34. Four years after his brush with death alongside Lady Thatcher, he was promoted by her to cabinet secretary and head of the home Civil Service at the relatively young age of 50.

He held the post for 10 years before retiring in 1998 after a 37-year career. He was then made a life peer, serving in the House of Lords as a crossbencher, a traditional neutral place to take up for a former cabinet secretary. He also became master of his old college at Oxford.

He was then recalled from retirement by Mr Blair to head an inquiry the Prime Minister was forced to concede. Mr Blair had resisted the demands for a further inquiry after the Hutton report had cleared him over the death of David Kelly, the government weapons expert who committed suicide. But the White House's decision to cave in to pressure for an inquiry in the US left him with no choice. Pushed into a corner, Mr Blair called for Lord Butler, whose old bicycle became a familiar sight again in Whitehall.

Sir Menzies Campbell, the Liberal Democrat foreign affairs spokesman, said yesterday: "Sir Robin has shown a scrupulous observance of his terms of reference, which is what you would expect from someone steeped in the Civil Service and the Government."

Lord Hutton was among those consulted by Lord Butler, but not listed among the witnesses in his report. The former peer's report was said by critics to be a whitewash. Lord Butler asked him if he had any advice to give his committee? "Yes," said Lord Hutton, "don't report".

Lord Butler may live to regret not taking that advice.

LORD BUTLER'S PANEL

SIR JOHN CHILCOT, 65

Diplomat, and former principal private secretary to William Whitelaw when he was Tory Home Secretary. Also spent seven years as permanent under-secretary until 1997, and was staff counsellor for the security and intelligence service. He was educated at Brighton College and Pembroke, Cambridge. He joined the Home Office in 1963 and in 1966 became assistant private secretary to the home secretary, Roy Jenkins. His club is the Travellers', the spooks' favourite.

ANNE TAYLOR MP, 57

A Blair loyalist. She is the chairman of the Prime Minister's Intelligence and Security Committee, which also cleared Mr Blair over the death of David Kelly. She is cleared to see most sensitive intelligence information. Believed to have argued in the Butler committee against "naming names", and was a big influence on the report, which again cleared Mr Blair of distorting the intelligence for the 45-minute claim. The MP for Dewsbury, she was Labour chief whip and Leader of the Commons.

MICHAEL MATES MP, 70

Tory MP for Hampshire East. A member of the Prime Minister's Intelligence and Security Committee. Defied Michael Howard to join the inquiry. Believed to have argued in favour of a more robust report, but is satisfied that, reading between the lines, it contains enough ammunition against Tony Blair and his Government. A former colonel in the guards, under John Major he became Northern Ireland minister responsible for security, including IRA intelligence.

LORD INGE, 69

Former chief of the defence staff from 1994 to 1997. Made clear that he thought the Joint Intelligence Committee had been asked to do things it should not have, mixing intelligence with public relations. Educated at Summer Fields, Wrekin College and Sandhurst. Commissioned in the Green Howards in 1956, he commanded Northern Army group on the Rhine. He was ADC General to the Queen from 1991 to 1994. A Field Marshal, he was given a life peerage in 1997.