JAILBIRD Michael Buchanan has been sentenced to three months behind bars for arming himself with a knife and threatening staff after going shoplifting.

But the 45-year-old who has spent most of his adult life behind bars was released immediately because of the amount of time he had been in custody on remand.

Buchanan, who has served a string of sentences for robbery, firearm offences and assault, was drunk when he was caught stealing jeans worth hundreds of pounds, a court heard.

David Chidgey, prosecuting, told Swindon Crown Court he was spotted stealing in Deben-ham's at about 4pm on Saturday, March 26.

"He was followed out by two members of staff and challenged by one male and one female," he said.

"He threw the bag back into the store and tried to walk away. One of the members of staff took hold of his arm and Mr Buchanan went for his right-hand pocket.

"He asked if he could be let go and was asked if he would be compliant. He replies 'No I'll stab you'.

"He was taken back into the store where he collapsed to the floor. He had a lot to drink. He was handcuffed.

"He was asked by the police if he had knife. He replied 'left side'.

A black handled kitchen knife with a 13 centimetre blade was found in his left pocket."

When he was questioned he admitted to taking five pairs of jeans and having the knife and he said he could not remember using the threat but accepted he might have.

Buchanan, of Manor Crescent, Moredon, pleaded guilty to theft, possessing a bladed article and threatening behaviour.

The court was told that he had 97 previous convictions, including robbery and having an imitation firearm in 1991.

He was also jailed for offences of assaults and attempted robbery, as well as threatening to kill a police officer in 2002.

Last summer he was also convicted of threatening store staff at Tesco's with a screwdriver after stealing drink.

Rob Ross, defending, said that while his client had the knife with him he had not brandished it at staff or tried to use it.

Since 1981 he said that Buchanan had been continually returned to jail having offending soon after his release.

He said that his client would seek the help of the Swindon and Wiltshire Alcohol and Drugs Service, as well as alcoholics anonymous when he was released.

Buchanan had spent about two months in custody on remand, he said, which was the equivalent of a four-month sentence.

Jailing him, Judge John McNaught said: "It is not for me to work out the effect of the sentence but what I am going to do is pass a sentence of three months."