Joseph Dowling, of Broom Hall, Broom in Bedfordshire created widespread panic when pictures on his camper van, parked outside the Law Society's offices in Chancery Lane, suggested it contained a bomb.

Dowling refused to leave the van and said he would detonate the bomb if there was any attempt to remove him.

London's Southwark Crown Court heard that, following a 28-hour stand off involving hundreds of police Dowling, finally left the van with the "bomb" - a simple power adapter.

You wanted to be caught red-handed to draw attention to your case and for that you must go to prison

Judge George Bathurst-Norman

Dowling parked in Chancery Lane on 10 January and waited for someone to spot the picture of the explosion on the van.

The note on the van read: "If I am forced to move in any way I will set two time switches, one at 10 seconds and the other at 15 seconds and leave the vehicle in haste."

Dowling had taken the action to try to highlight a long-running legal dispute with Bedfordshire law firm Leeds Day.

Judge George Bathurst-Norman said he had no doubt that Dowling honestly and genuinely believed he had been "fobbed off" by the Law Society following his complaint about the firm of solicitors and a matter involving just over £587.

'Considerable ability'

"You wanted to be caught red-handed to draw attention to your case and for that you must go to prison," he said.

After the hoax and Dowling's arrest, the Law Society had acknowledged the solicitors were in error.

Ben Summers, prosecuting, said: "The Commissioner's reserves for the whole of London were called in, as was a terrorist support unit and mounted police officers.

"Lighting and CCTV were put in place to monitor the situation.

"There were explosives officers, a hostage negotiating team, specialist firearms officers and firearms dogs on the scene, along with anti-terrorist branch officers, two ambulances and two fully equipped fire engines."

The judge said he gave Dowling full credit for his age, his previous "impeccable" character and the fact he was clearly a "highly regarded" person of "very, very considerable ability".