Seven men who spent months planning a multi-million pound raid on a computer company have been jailed.
The London-based gang admitted conspiring to rob computer equipment from Comstor UK in Cirencester, Gloucs.
The men were arrested last December by armed officers before they could enter the firm's warehouse.
At Harrow Crown Court, ringleader David Thomas, 37, from Luton, was jailed for nine and a half years. He also admitted trying to bribe a police officer.
In sentencing, Judge Alan Greenwood described the group as a professional criminal gang.
They were placed under police surveillance following a tip-off
They had been placed under police surveillance early on in the planning of the heist following a tip-off, police said after sentencing.
The gang had spent months "meticulously planning" the robbery and travelling to Cirencester several times to observe the warehouse.
On Christmas Eve they drove to the site in two stolen cars and two vans, armed with coshes, ammonia, heavy-duty tape and handcuffs.
Around £26m of computer equipment was in the warehouse at the time, police said.
Examination of the two vans suggested that they would have been able to carry approximately £4.5m worth of equipment, the court was told.
Ringleader Thomas was jailed for nine-and-a-half years for conspiracy to rob and perverting the course of justice.
While on bail over the offences, Thomas offered £50,000 to a Flying Squad officer in an attempt to sabotage the prosecution case against him.
The officer alerted the Metropolitan Police's anti-corruption command about the bribery bid and Thomas was recorded trying to bribe him.
"If we can get this thing crushed, yeah...you come up with a figure, yeah...," Thomas was heard saying in recordings played out to the jury.
"I'm being honourable cos you know me I'm not really a prison man, I'm a businessman.
"...If you agreed and we agreed...would give you half the thing yeah up front then the other half...50 is not a problem."
Det Supt Gordon Briggs said: "The Flying Squad officer exhibited integrity and courage in playing the role of a corruptible officer and ensuring that Thomas could be additionally prosecuted for this crime."
Thomas was sentenced to seven years for conspiracy to rob and two-and-a-half years for perverting the course of justice.
Lyndenn Willoughby, 36, from Enfield was sentenced to seven years for conspiracy to rob.
Atilla Kadir, 35, of Woodberry Down, north London, was sentenced to four-and-a-half years for conspiracy to commit burglary.
Anthony Diop, 34, from Hackney, north London, was sentenced to three-and-a-half years for conspiracy to commit burglary.
John Tripp, 22, of no fixed address, was sentenced to four-and-a-half years for conspiracy to commit burglary.
Tyrone Brown, 25, St Paul's Road, north London was sentenced to four-and-a-half years for conspiracy to commit burglary.
Paul Lewis, 32, of Blackstock Road, north London was sentenced to four-and-a-half years for conspiracy to commit burglary.