The BBC's John Andrew: His barrister said Alford had been the victim of a professional sting

The actor had earlier been found guilty by a jury at London's Snaresbrook Crown Court of one count of supplying 2.036 grammes of cocaine to an investigative reporter, as well as a similar charge involving 11.9 grammes of cannabis resin.

Sentencing him at the same court on Wednesday, Judge Stephen Robbins told Alford that he had taken into account that fact there had been an element of entrapment in the case, and this had gone in the actor's favour.

'Elaborate subterfuge'

Alford began his acting career at the age of 11 as the classroom rebel Robbie Wright in the children's BBC TV programme Grange Hill.

In August 1997, he had been lured to the Savoy Hotel in central London by a journalist posing as an Arabian prince and secretly filmed supplying cocaine and cannabis.

Alford on his way to court last year

The court had heard Alford, 27, was so taken in by the "elaborate ... well-planned subterfuge" he even bowed to the bogus royal, who was in fact News of the World investigative editor Mazher Mahmood.

The prosecution said Alford, whose fiancée Tina Mahon was in court to hear the sentence passed, had acted out of "greed" after being offered the chance to join a celebrity line-up at the opening of a nightclub in Dubai.

Judge Robbins told Alford that entrapment had clearly played a significant part in what he did, but greed had also been a major factor.

Cocaine habit

"You were undoubtedly motivated by the desire to earn even more money than you were earning as a successful actor, believing you would be opening a nightclub in Dubai.

"There was a strong element of entrapment but you willingly went along with the idea. You had plenty of opportunity when you left to fetch these drugs to distance yourself from it."

The judge also told Alford that he also had to bear in mind the fact the former actor had previously used cocaine himself, sometimes spending up to £500 on his habit, before weaning himself off it.

He reminded Alford that he had told the court of seeing friends "go down the road to hell from this drug".

He said: "People in such circumstances who then agree to supply that very same drug can and should expect little mercy from the courts."

Justice 'tempered with mercy'

The judge accepted that Alford also had a "positive side", and had helped many people. This had been shown in the "many moving letters" which had been written to the court on his behalf.

Yet while he said he would "temper" justice with "mercy", by reducing the time Alford would otherwise have spent in prison, he said it was his public duty to pass an immediate custodial sentence.

Alford was jailed for nine months for supplying the cocaine, with a two-month sentence to run concurrently for the cannabis charge.

The actor was also ordered to pay £3,000 towards prosecution costs, as well as meet a £300 confiscation order - the money given to him by the reporter to buy the drugs - or face a further 14 days in prison.

Alford, from Hadley Wood, Hertfordshire, had represented himself during the 10-day trial.

After the story broke last year, he was sacked from his £50,000-a-year role in the ITV television drama, based on the lives of a team of firemen.