Posted December 23, 200718 yr GANGLAND mobsters are threatening to KIDNAP troubled rock star Amy Winehouse unless they get a ransom of £100,000. Jailbird villains put the squeeze on the singer's terrified hubby Blake Fielder-Civil as he languishes in prison awaiting trial.Now he has sent Amy a frantic warning: Be on your guard and stay safe.It's been a bad week for 25-year-old Blake, on remand in Pentonville for alleged assault and conspiracy to pervert the course of justice.He had gone cold turkey and kicked heroin behind bars but The News of the World has discovered he got: LURED back on drugs by gangsters determined to soften him up for the kidnap plot, BUSTED in a random spot check that proved positive for Class A drugs, and BANGED up in the sex perverts' wing as punishment. A source inside the tough jail told us: "Blake's petrified. He's living in fear for Amy's life AND his own. "At first he thought the guys in here were just trying their luck but the threats have got really bad. He's now under no illusions and convinced they'll go through with what they say. "They've ordered Blake to pay the 100 grand into a secret bank account within the next few days or else...Amy will be snatched and harmed. "She's at her weakest right now, and what with her wandering the streets in the dead of night she's at massive risk. "Blake knows it'll be easy to bundle her off in a car without anyone batting an eyelid." Our insider revealed how tattooed Blake was tempted and pressured by his enemies inside to get back on heroin—in a bid to weaken his mind so he'd crack and pay up the cash. And earlier this week he was targeted for a random drugs test. Blake's urine sample proved positive for a Class A substance, believed to be cocaine or heroin. As punishment he was moved from the prison's general G wing to the secure D1 unit— usually for sex offenders police informants who are automatically a targeted for other lags. He will now spend Christmas with a roll call of rapists, paedophies and other pervert.Our source said: "Getting involved again like this is the last thing Blake needs. He'd finally got clean after a monstrous year battling drugs. Prison has been tough on him but getting off heroin and stuff was the one good thing. "Now he's panicking that he won't ever be able to resist the heroin lags have been shoving under his nose." BUT life incarcerated with the sex fiends could prove a blessing in disguise. Our man on the inside said: "In this isolated unit Blake will now find it more difficult to get his hands on drugs and the guards will be keeping a much closer eye on him." "Plus the guys who are threatening to abduct Amy can't get to him there. "So he's hoping that it'll be case of out of sight, out of mind, and the faces who are out to get at him will find someone else to pick on." In the week when 24-year-old Amy was arrested and quizzed by police over Blake's case—as predicted by the News of the World last Sunday—he got word to her, warning of the urgent threat to her safety. Now on bail, the painfully-thin star promised to lie low. The jail source added: "Blake's so scared of these toughs trying to strongarm him that he's had meetings with his legal representatives demanding they put pressure on officials to keep him safe." Last week we revealed how police had confiscated Amy's mobile phone records, bank details and computer software as they trawled for any clues connecting the star with Blake's case. Cops also visited her accountants to track her financial dealings. Blake and pal Michael Brown are accused of assaulting pub landlord James King in Hoxton, east London, last year. It is also alleged they then plotted to pervert the course of justice by offering Mr King a significant amount of money to withdraw his allegation and leave the country.