Two armed robbers from Derry were this week jailed for a total of 23 years in Dublin.

The men were arrested and convicted after a cash box they attempted to steal emitted a high pitch noise and red dye. The confusion caused the bungling pair to crash into an Irish Army vehicle during their attempted escape. They were also convicted of the false imprisonment of a taxi driver during the high speed chase.

The details emerged at the Special Criminal Court trial of Charles Anthony Deery, 42, from Derry but with an address at Aughrim Street, Dublin, and Dermot McFadden, 39, of Kildrum Gardens, Creggan. The court heard how during the escape they had to ask a taximan, who they had forced into the boot of his own vehicle at gunpoint, how to drive the car. The court was told they then crashed the hijacked taxi into an Irish Army vehicle after the stolen cash box emitted the high pitched noise and red dye.

The money had been taken from a security guard who was delivering it to a Post Office in July 2010.

McFadden and Deery were then arrested as they tried to hide in a funeral home.

They had also been captured on CCTV during the ill-fated adventure.

All E30,000 which had been in the cash box was recovered.

During their escape attempt, the court heard, that three men produced a gun and forced a taxi driver into the boot of his cab before driving to Prussia Street.

They had told him they were on an IRA “operation.”

The robbers, disguised in glasses, wigs and hats, then struggled to drive the taxi, which had an automatic gearbox. They had to get instructions from the imprisoned driver who was locked in the boot.

After crashing the vehicle McFadden and Deery fled into Burke’s Funeral Home where they were apprehended.

A third accomplice made good his escape.

A detective with An Garda Siochana told the court that Deery had four previous convictions in Northern Ireland.

They included convictions in 1994 for conspiracy to murder, conspiracy to cause an explosion and possession of explosives - convictions for which he was sentenced to 20 years in prison.

McFadden had a total of 14 previous convictions in Northern Ireland, ranging from road traffic offences to theft.

Charles Deery was jailed for 13 years for robbery in July and the false imprisonment of a taxi driver. Dermot McFadden was sentenced to 10 years for the same offences.