Steven Roose, 36, was in custody on other matters when he told police that he had been involved in a terrifying attack on the proprietor of the Shibden Mill Inn last August.
Roose admitted that he had been armed with a machete when he confronted Simon Heaton after he had put a bag containing over £7,000 in takings into his Aston Martin car.
Mr Heaton described the weapon as looking like something of the film Pirates of the Caribbean and said the robber was waving it around as he demanded the money.
Two other men also joined in the robbery and as Mr Heaton ran back into the premises he heard the sound of the passenger door window being smashed.
After grabbing the bag the gang fled in a Vauxhall Insignia car and Bradford Crown Court heard today (Friday) that none of the stolen cash had been recovered.
Roose, of Moor End Road, Halifax, also told police that he had been involved in another armed robbery back in October 2006 when two masked men, armed with a sawn-off shotgun and an iron bar, stole more than £50,000 from a Group 4 Security guard as he delivered cash to an ATM at the service station on Pellon Lane.
Prosecutor Nick Adlington described how the guard was ushered back into the service station at gunpoint before the robbers fled with the cash.
Mr Adlington said Roose claimed that he had acted as the getaway driver for the two armed robbers that morning and he went on to confessed to a third robbery at a house in Ash Tree Gardens, Mixenden, October last year.
The court heard that Roose and an accomplice had been wearing a balaclava and a clown mask with red hair when they confronted unsuspecting Claire Navin as she opened her door.
At the time of the robbery the intruders were carrying a CS gas canister and an imitation gun and Miss Navin was punched in the face before being manhandled upstairs and tied to a bed.
The men stole cash from the house and Miss Navin was eventually able to free herself and alert the police.
Roose told officers that he had carried out that robbery because he didn’t like Miss Navin’s partner and they had to punch her to make her know they were serious.
Barrister Jayne Beckett, for Roose, said he volunteered all the information linking him to the three robberies.
“This defendant has clearly made a decision to draw a line under the terrible criminal past that he has,” she added.
She said Roose had shown real remorse and it was an unusual case of a hardened criminal making the decision to stop and sort things out.
Judge Jonathan Rose told Roose that the robberies were in “a wholly different league” from his previous offending and they professionally planned crimes which were executed for significant gain.
“In short you commit offences because you want to and because you have in the past decided to make a living from crime rather than in an honest and decent fashion,” he told Roose.
Judge Rose explained that the starting point for the sentence was a total of 19 years in jail, but he had to give Roose a discount of a third for his guilty pleas to all the robberies.
The judge said Roose would also receive further credit for the fact that he had told the police about his involvement and that reduced the jail term to 11 years.
But Judge Rose said the nature of the offending indicated that Roose was a dangerous offender and it was necessary to impose an extended licence period of four years onto his sentence.