As a "painstaking" investigation swung into operation, one of his prints was found on a ferry ticket linked to a "dummy run" for a converted lorry used in the attack.
It was also discovered on an ashtray in a truck stop in Carlisle, Cumbria, which was used for an overnight stay during the actual bombing trip three weeks later, Woolwich Crown Court in south-east London was told. The thumb print was also retrieved from a magazine found with other allegedly incriminating evidence a few miles from the scene of the blast.
But the name of its owner remained a mystery until James McCardle, 29, a labourer, was arrested in Northern Ireland in April last year - 14 months after the blast which killed two people, injured many others, caused an estimated pounds 150m damage, and signalled the end of an 18-month IRA ceasefire.
"His identity was unknown to the police until his thumb print was found to match that of Triple Thumb Print Man," said John Bevan QC, for the prosecution. "He was brought to London and interviewed ... he declined to answer questions."
However, his thumb print along with finger and palm prints which were also matched to him, "provide the evidence, we suggest, which links him to this offence in such a way as to make him a central figure in the bombing".
Mr McCardle, from Crossmaglen, Northern Ireland, denies conspiring to cause an explosion likely to endanger life or cause serious injury to property between 30 October 1995 and 10 February 1996. He also denies murdering Inam Bashir and John Jeffries, who died in the blast on 9 February 1996.
Mr Bevan said the Canary Wharf bombing was a "sophisticated scheme" involving a number of terrorists in an active service unit of the IRA.
The terrorists converted a British Gas lorry into a car transporter containing a secret compartment big enough to contain more than a ton of home-made explosive. Its identity was then changed with the help of false number plates.
Mr Bevan said the following month Mr McCardle, using yet another identity, brought the lorry back, this time carrying the explosive. Cameras along the M6 were later found to have recorded its progress.
He said that on the day of the explosion the vehicle was driven to River Road in Barking, east London. Once there the trailer the vehicle had carried to help complete its disguise, as well as other items, including a magazine and tachograph readings, were abandoned to avoid the possibility of incriminating evidence being found at the scene of the bombing.
"This was an exercise in deception with the lorry and its driver at the very heart of that deception.The mistake they made - it could never have occurred to them in a million years - was that the River Road site would be found and linked to the bomb," Mr Bevan said.
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