Probably the most feared man in British politics - Alastair Campbell - has spoken of his experience of a nervous breakdown, describing it as a "24-carat crack-up".

Downing Street's director of communications suffered a mental crisis in 1986, when working as news editor for Eddie Shah's newly launched Today newspaper.

The Downing Street spin doctor has never made any secret of his mental illness, which he said was partly fuelled by heavy drinking.

Now Mr Campbell, who was the prime minister's official spokesman until a promotion to the "backroom" at No 10 last year, has told his story for an exhibition by the mental health charity Mind Out in Mental Health.

At the 1 in 4 exhibition - a reference to the proportion of Britons who suffer from mental illness - he said: "I hit the bottle pretty hard, got completely manic and cracked."

Mr Campbell said he realised he had been drinking "vast amounts" of alcohol. He is now teetotal.

The prime minister's communications director, now 44, said he was proud of the way he had rebuilt his life.

"I feel about the whole breakdown business that it is where I sorted myself out - personally, politically, professionally, everything," he added.

Other contributors to the exhibition include comedian Paul Merton, who spent six weeks in the Maudsley psychiatric hospital in south London after a "manic episode" in 1989; actor John Hannah, who talks about depression; and the actress, Patsy Palmer, who suffered a breakdown in 1997 while working on EastEnders.

The 1 in 4 exhibition is at the.gallery@oxo in Oxo Tower Wharf on London's South Bank from February 7-17.