By Mike Costello and Matt Slater

Harrison was in defiant mood in front of the press on Thursday

WBO featherweight champ Scott Harrison has told BBC Sport that he is as fit as he has ever been despite spending five weeks in a Spanish prison.

He defends his title against Nicky Cook on 9 December - only three weeks after his enforced stay in Malaga.

Sporting a tan gained whilst running in the prison yard, the 29-year-old Scot said he was ready to face Cook.

"I was training for a month before going in, so in some ways the rest has done me good," said Harrison.

News conference: Scott Harrison

Harrison was in London on Thursday to help promote his fight against the 27-year-old Cook, a former British, European and Commonwealth champion, at the Excel Arena in the city's Docklands.

And the Cambuslang-born boxer was in relatively bright spirits as he explained his prison training regime.

"I trained three times a day by running around the yard, circuit training and skipping with a rope that some of the other prisoners made for me," said Harrison, who was in prison on assault charges.

I will be ready on the night - I'm always mentally right to fight, I'm a fighter Scott Harrison

The other inmates also made some weights by "snapping a broom handle in half, cutting a tin can in half and filling the two halves with cement".

Harrison also watched his weight whilst in custody but he admitted that the quality of the food made that quite easy.

"I was eating two meals a day and it was mostly fish and boiled rice, which is what I eat when I'm training anyway," he said.

"But that has helped me get my weight down for the fight."

606 DEBATE: Can Harrison get his career going again?

The British Boxing Board of Control has already given its approval for the fight after Harrison underwent a medical examination last week.

Harrison, however, admitted that his stay in custody was not entirely without downsides.

"There were times, as (the bail application process) dragged on, that I worried if I would be released in time to make the fight," he said.

"In Spain it's always 'manana, manana' (tomorrow, tomorrow) and that's what happened."

He would have been stripped of his title if he had failed to defend it against Cook.

Harrison looked in good nick after his �19,000 release on bail

He also admitted that he did not want to attend Thursday's press conference but promoter Frank Warren had insisted.

"It's been a pain to get him down here. He didn't really want to come because he has his training schedule but I needed him down here," Warren confirmed.

Harrison, who has admitted to problems with alcohol and depression, was arrested in Spain on 6 October after several alleged offences, including an assault on a police officer.

He faces another court hearing in Spain on a date which is still to be set.

The fighter, who pulled out of his last fight in Belfast in May because of his personal troubles, is also scheduled to go to court in Glasgow in February to answer a number of charges, including three of assault.

Harrison, who regained his world title four years ago when he avenged his defeat to Manuel Medina, has a 26-2-1 record with 14 KOs, while the Dagenham-born Cook is unbeaten in 26 fights.

"I will be ready on the night. I'm always mentally right to fight, I'm a fighter," said Harrison, who has made 11 successful defences.