Robert Chesshyre: Innocent once and for all, I hope

George Davis, the bank robber at the centre of one of the highest profile miscarriage of justice cases of the post-war era, will learn this week – 37 years after he was convicted and then pardoned – whether, in the eyes of the law, he was, after all, rightly convicted at the Old Bailey as one of a gang of armed robbers who raided an electricity showroom half a lifetime ago.

The campaign to free Davis gripped the nation. Prominent "George Davis is Innocent, OK" graffiti appeared across London; supporters crashed vehicles into the front offices of Fleet Street newspapers and the gates of Buckingham Palace; they smashed a window at the British embassy in Paris; and one night pro-Davis crusaders climbed into Headingley cricket ground in Leeds and dug up the wicket in the middle of an Ashes Test. After that everyone sat up and took notice.

George Davis's appeal is a blast from the past, akin to the return from Brazil of that other oldie villain, Ronnie Biggs. Those who remember the original furore will be gripped again by the final chapter in a cops-and-robbers saga straight from the era of The Sweeney. On 4 April 1974 five armed men attacked a security guard, shot a police officer, ran down another and evaded capture in a high speed chase, hijacking four cars at gunpoint. Was one of the men Davis?

I was the first reporter to investigate in detail Davis's claims to innocence, and I concluded that, villain though he might have been (on release he was convicted of a bank robbery), in the days when (almost) everyone trusted the police, he had been wrongly jailed for 20 years. I believe my reporting of the flaws in the case still holds up, and I am hoping that the Court of Appeal concurs.

Primed by Davis's wife, Rose – a doughty fighter for his innocence – I roamed the East End of London demimonde of scrap metal merchants and market stall holders (terms like "demimonde" were still in use in those Life on Mars days). Davis's mates, all criminals – most decked out, as was then the fashion, with gold jewellery – were nice to me (I couldn't buy a round): they hoped that my piece would aid the campaign. I had mixed feelings about their company: I would not have enjoyed facing the wrong end of their shotguns.

Davis's case was that he was driving his minicab at the time of the robbery. Given the character of his associates, some alibi witnesses (several, including the owner of the cab company, themselves had criminal records) were less than convincing: no vicars or magistrates among them. I wrote at the time: "I could see why a jury might not believe one or two of the witnesses."

There were 308 items of evidence, but none that could be linked to Davis. The prosecution relied on identification and an alleged statement by Davis: he claimed to have been "verballed", then all too possible. Although several cops identified Davis, they had all been travelling together and had an opportunity to collude, and in a series of ID parades 34 of 39 witnesses failed to pick him out.

Although I – like Davis's Old Bailey defence – was unable to "prove" his innocence, the case against him was suspiciously thin. I decided that there was at least sufficient uncertainty for the prosecution to fail the "reasonable doubt" test.

Roy Jenkins, then Home Secretary and presumably of the same mind, released Davis by way of Royal Pardon, though the conviction stood (hence the belated Court of Appeal hearing), and Davis walked free both to cheat on Rosie (who died two years ago) and to carry out the subsequent bank robbery.

It is strange seeing him now – at the appeal hearing looking every inch a retired stockbroker – far removed from the boyish gangster of yesteryear. Maybe after this week's judgment those graffiti of long ago can be repainted. Thirty-seven years on, George Davis may indeed finally and legally be Innocent, OK?