Revealed: The pressure on Dr Kelly in the weeks, days and hours before his death

Three hours after he walked out his Oxfordshire home for the final time, David Kelly's mobile trilled into life. It was 6pm on 17 July and his line manager at the Ministry of Defence was trying to get in touch yet again.

After a fortnight of interrogation by MoD officials and MPs and repeated phone calls from civil servants, this was one more call about the BBC's row with the Government over intelligence on Iraq.

Bryan Wells, the head of counter-proliferation at the MoD, wanted to check yet again exactly which journalists Dr Kelly had spoken to, when and under what circumstances. But when Mr Wells called the scientist's mobile, it simply rang. And rang. And rang. Within 24 hours, Dr Kelly's body was found in a beauty spot, his left wrist slashed.

Yesterday, the Hutton inquiry gave the clearest picture yet of the final weeks, days and hours of the weapons expert's life, exposing the immense pressure he was under. Delivering the most electrifying and important testimony so far, Mr Wells, at times wittingly, at times unwittingly, shone invaluable light on the events that led up to Dr Kelly's death.

For the first time, court 73 heard details of the interviews MoD officials conducted, the protection or lack of it offered to the man at the heart of a media maelstrom, and the memos that flew between the ministry and the Foreign Office and Downing Street.

The inquiry was told how senior MoD officials went through, line by line, what they called "tricky issues" Dr Kelly had to confront. How he was told to act "according to your conscience" and how he was warned in a formal letter that "disciplinary action" still hung over him.

Mr Wells first met Dr Kelly when he was appointed his line manager in August 2002. The pair grew to know each other well as they went to and from New York as the UN strove to tackle the issue of Iraq's weapons of mass destruction. Dr Kelly had a much warmer relationship with Foreign Office officials, whom he counted as friends as well as colleagues.

The first clue Mr Wells had that Dr Kelly may have spoken to Andrew Gilligan, the BBC reporter, was on 19 June, when he was contacted by Martin Howard, the deputy director of defence intelligence.

On 1 July, Mr Wells received a letter from Dr Kelly, dated 30 June, in which he admitted he had met Mr Gilligan but denied he was the main source of the Today programme claim that Downing Street "sexed-up" a dossier on Iraq.

On 4 July, Dr Kelly was subjected to his first interview at the Holborn office of Richard Hatfield, personnel director of the MoD. He was first warned that a public statement may have to be issued that an MoD official had come forward and admitted contact with Mr Gilligan. He was warned of the seriousness of the matter and then taken in minute detail through the "significant discrepancies" between his and the BBC reporter's accounts of their meeting.

Mr Wells said Dr Kelly was "somewhat uncomfortable" during the meeting. Dr Kelly admitted that he had told Mr Gilligan the 45-minute claim had been put in the dossier "probably for impact".

The meeting concluded with those present agreeing that Dr Kelly may have been a background source for Mr Gilligan and had strayed beyond normal rules about contacting journalists. He had been "read the riot act" but essentially he was in the clear.

Dr Kelly may have thought that was the end of the matter, but other parts of Whitehall were not so forgiving. Richard Hatfield, the MoD's personnel director, wrote to Sir Kevin Tebbit, the permanent secretary of the ministry. The matter was then "referred up" to the Cabinet Secretary, Tony Blair's chief foreign affairs adviser and the head of MI5. Most importantly, it was also referred to John Scarlett, the chairman of the Joint Intelligence Committee, which had drafted the dossier.

On Sunday, 6 July, Sir Kevin wrote a letter claiming that "the finger points strongly at David Kelly as Gilligan's source".

On Monday, 7 July, Mr Scarlett wrote an ominous note to Sir David Omand, Downing Street's head of intelligence and security. "Kelly needs a proper security-style interview in which all of these inconsistencies are thrashed out." Similarly, a memo from Dominic Wilson, private secretary to Sir Kevin, called for "a more intensive interview with Dr Kelly".

That morning, Mr Wells, phoned Dr Kelly to tell him to attend another interview at 4pm in London. It was clear this second interview was indeed "security style". The questions were tougher, more relentless. Again, the discrepancies were pored over.

Dr Kelly was handed a draft press release revealing that an official had met Mr Gilligan without authorisation. Dr Kelly approved the release and it was sent out on 8 July. The hunt for his identity had begun.

On 9 July, Dr Kelly was forced to flee his home as the media sniffed around the story. He was then called to appear before the Commons Foreign Affairs Committee and the Security and Intelligence Com-mittee. Dr Kelly "expressed some concern" about appearing before the Foreign Affairs committee in public. When pushed by Mr Wells, he replied: "If I'm asked, I will do it."

Yet another meeting was arranged with Mr Hatfield and Dr Kelly at the MoD, this time on 14 July to discuss what he would say to MPs.

It was clear that this meeting then turned into another grilling. Mr Hatfield went through what he described as "tricky areas".

On the key issue of what he would tell MPs about the Gilligan source, Dr Kelly asked "Can I say I don't believe I am?". Mr Hatfield replied: "That is a matter for your own conscience and the facts."

Crucially, at the end of the meeting, Dr Kelly was handed the formal letter that resulted from his earlier meetings. It had a chilling final paragraph warning of further disciplinary action if events changed.

Dr Kelly duly gave evidence to the MPs on 15 July and then to the ISC on the following day. After the ISC meeting, Mr Wells told him a delayed trip to Iraq was back on again. He would fly out on 25 July. Dr Kelly was "very pleased".

But that afternoon, it was clear the matter was not over. Mr Wells phoned Dr Kelly to say he needed full details of his contacts with journalists to answer a letter to the foreign affairs committee and for a parliamentary answer to Andrew Mackinlay MP about the issue.

On 17 July, the day he died, Dr Kelly rang Mr Wells at 9.45am to say he had e-mailed his response on his journalistic contacts. At around 1pm, Mr Wells rang again to say he wanted to check his answers. "That was the last conversation I had with David," he said.

THE COUNTDOWN

30 June: Dr Kelly tells Bryan Wells about meeting Andrew Gilligan.

4 July: Dr Kelly subjected to his first interview at Richard Hatfield's office. Warned public statement may have to be issued.

6 July: Sir Kevin Tebbit writes letter claiming: "the finger points strongly at David Kelly as Gilligan's source".

7 July: Dr Kelly undergoes second MoD interview and"security-style briefing".

8 July: Press release confirms civil servant involved.

9 July: Dr Kelly is forced to flee his home after he is named in newspapers.

14 July: MoD meeting where he is grilled by Mr Hatfield over what he will say to Foreign Affairs committee.

15 July: Dr Kelly gives evidence to Foreign Affairs Select Committee.

16 July: Dr Kelly appears before the Intelligence and Security Committee

17 July: Dr Kelly dies.