New spy chief is the ultimate Deadhead

British intelligence may get it wrong on such matters as weapons of mass destruction but there will soon be one subject on which they can be trusted to provide full and reliable information.

Alex Allan, the Whitehall mandarin appointed by Gordon Brown to be the new British spymaster, is also a world authority on the Grateful Dead, one of the biggest bands to emerge in California in the late Sixties love-and-peace era when kaftan-wearing visitors to San Francisco were urged to wear flowers in their hair.

Their dedicated fans, known as Deadheads, followed them from gig to gig, like one big extended family. They were so well behaved that one California police chief said he would rather be on duty at nine Grateful Dead concerts than one American football game. Their placid conduct could, of course, be largely attributed to the soporific effects of marijuana.

Jerry Garcia, lead singer of the Grateful Dead, has been dead (in the normal sense of the word) for 12 years but Deadheads are with us still. A fans' website that lists every album, every track and every piece of trivia known about the group is lovingly compiled by a Deadhead called Alex Allan, the same Alex Allan who, by day, works as one of Britain's top civil servants. Yesterday, he was named as the next chairman of the Joint Intelligence Committee, the apex of the Government's spy network.

Throughout the Cold War, it was the JIC which updated prime ministers on what the West knew about Soviet military capabilities, a job it did well. With the Cold War over, the JIC has had some difficulty finding a new role but its influence reached a peak in 2003 under the chairmanship of John Scarlett, when it told the Cabinet about Iraq's alleged weapons of mass destruction and provided Tony Blair with a reason for going to war.

Mr Allen is not a professional spy but he does have a head for accurate and minute detail, as a visit to his Grateful Dead lyric and song finder website will verify. He joined Customs & Excise as a 22-year-old university graduate in 1973 and rose through the ranks at Whitehall to become principal private secretary to John Major when he was Prime Minister in 1992.

During a rail strike in the 1980s, he decided to windsurf to work along the Thames in his suit and bowler hat, with a briefcase and furled brolly in one hand. As he passed Big Ben, a gust of wind tossed him into the river.

In the first four months of Mr Blair's premiership, Mr Allen stayed at Downing Street to oversee a smooth changeover and was able to furnish the new Prime Minister with an interesting, if useless, piece of intelligence.

As a student at Oxford, Mr Blair was the lead singer in a rock group called Ugly Rumours, but had forgotten whence the group took its name.

Mr Allan reminded him it was taken from the cover of From The Mars Hotel, a Grateful Dead album. Mr Blair was so impressed with Mr Allen's website that in 1999, he asked him to be the government's "e-envoy", responsible for dragging the Civil Service into the age of the internet. He is currently the Permanent Secretary at the Ministry of Justice.