The BBC Radio 2 presenter was also ordered to pay �200 costs at Horseferry Road Magistrates Court in central London.

The broadcaster was suspended by the BBC when the drug allegations were published in the News of the World in April this year.

Reporters, claiming to be interested in setting up a new radio station, had arranged a meeting with Walker at the Grosvenor Park Hotel in central London.

Magistrate Rosmond Keating criticised the journalists' methods and the "filth" they had written about Walker.

After the hearing, Radio 2 announced that Walker would be returning to his drivetime show.

The court heard that Walker had turned to cocaine while facing pressure at work, the loss of both his parents in close succession and the end of a long-term relationship.

'Source of strength'

But Mrs Keating told the 54-year-old he had a duty to maintain higher standards of life than other people because of his position as a celebrity.

However, she noted that he had sought help for his addiction and said: "I hope some good will come out of this appalling incident."

Outside court Walker, of Leigh, Wiltshire, thanked his family and listeners for their support, saying they had been "a great source of strength".

The DJ said he was "extremely sorry" for the embarrassment he had caused to family, friends and the BBC.

He said: "I am trying my very best to put my troubles behind me on a daily basis."

'Drug became an enemy'

In court Walker's counsel, Antony Chinn, said of his client: "He found himself alone and working hard and he turned to the occasional use of cocaine.

"But what started off as a crutch or a friend soon turned into an enemy. It is a very addictive drug."

He said Walker had been considering getting help even before he was exposed.

No date has been decided for Walker's return to Radio 2. An internal inquiry was launched by BBC Radio director Jenny Abramsky when Walker was suspended.

'Deep regrets'

A statement issued by the station said: "Johnnie Walker admitted that he had used cocaine but absolutely denied dealing in drugs.

"He stressed his deep regrets and faced up to his need for help. With no pressure from the BBC he underwent a rehabilitation programme, paid for by himself.

"The BBC is adamant that it does not tolerate the use of illegal drugs. However, the BBC Radio management is impressed by the way Johnnie has handled this crisis in his life and has sought professional treatment."

The statement said Radio 2 had also considered the views of listeners when considering Walker's future.

It said: "Now that the court case is over, Radio 2 has taken account of Johnnie's sincere regret for what happened, of his ongoing resolve to tackle his problem, and of the views of his Radio 2 audience and is pleased that Johnnie will be reuniting to the network at a date to be discussed with all parties."