An armed robber is appealing against his conviction claiming that he was high on a mind-bending cocktail of drugs when he confessed to police.

Michael Holliday claims he even bragged to detectives about non-existent raids he dreamed up after bingeing on vast amounts of cocaine and amphetamines in police custody. And his solicitor says despite him suffering from drug-induced hallucinations, a doctor had deemed him fit to be grilled by detectives.

Holliday was convicted of two attacks carried out in Bradford - one which saw the robber open fire on a female security guard and escape with £15,000 - and was jailed for 12 years. His appeal bid has been made after new evidence emerged which suggests his innocence in the gun raid.

His solicitor Jeremy Pinson said: "I have seen a doctor's report from the time which said Michael was under the influence of up to four narcotics and there was of chance of him experiencing hallucinogenic flashbacks. Incredibly, it declared him fit to be interviewed and prescribed him two Tamazepam tablets." A judge later heard how Holliday told police he had "a hundred more robberies planned" and had been carrying out raids "all of his life".

Holliday has now served seven years as a Category A prisoner, almost six of them in solitary confinement following failed escape bids, hunger strikes and rooftop protests supporting his claims of innocence.

Detectives recently unearthed evidence suggesting Holliday may well be unconnected to the £15,000 raid.

Speaking from his jail cell in HMP Frankland, Durham, the 43-year-old said he was quizzed for six days without legal advice after taking up to 40 grams of cocaine and amphetamines he had hidden on him at the time of his arrest in July 1996. Holliday said police eventually rushed him to hospital. "I had completely lost the plot by then," he said.

He said he went days without sleep, adding: "I decided I would admit to anything and everything. I even admitted to dozens of crimes that had never even occurred. I was high as a kite. The police took advantage of my state of mind."

Mr Pinson said he believed there was now "incontrovertible evidence" Holliday was not behind the £15,000 gun raid but explained that his case had to be referred to the Court of Appeal before the charge could be dropped officially. It is being processed by the Criminal Cases Review Commission, an independent body with the power to send alleged miscarriages of justice to the appeal court.

Both robbery convictions, for which he received two concurrent 12-year sentences, were being examined by the CCRC as his admissions to them arose from the same police interviews, said Mr Pinson.

Holliday said he would have denied the charges at a trial but the barrister representing him at that time advised him not to, saying he risked a life sentence if he was convicted. Mr Pinson said Holliday was due to be considered for parole in six weeks' time. He said if just the gun attack was officially quashed before the hearing, his chances of release would be greatly improved.

A spokesman for West Yorkshire Police confirmed the force was liaising with the CCRC.