A thief has been sentenced to 14 weeks in jail for attempting to smuggle a mobile phone into Horfield Prison hidden between his buttocks.

Mark Grifiths, of Murray Street, Bedminster, was called before Bristol Magistrates' Court in February for attempted theft and obstructing a police officer.

The 36-year-old has expected to be set free while a pre-sentence report was prepared, the court heard.

But magistrates instead sent him to jail, and the panicking prisoner slipped the phone into his boxer shorts so that he could call his family from behind bars. When Grifiths got to Horfield prison, security guards became suspicious.

Kirsty Allman, prosecuting, said: "He was searched and asked by officers if he had anything on him. He said no, but security officers began to think that he had something in his underwear. He was asked a second and a third time if he had something, and again he said no."

But as Grifiths fumbled with the waistband of his boxer shorts, the phone fell out on to the floor, and he said: "You've got my f*****g phone. Happy?"

Defending, Selena Hunt said that Grifiths' action had been carried out "on the spur of the moment".

She said: "He wasn't expecting a custodial sentence, and said he just slipped the mobile phone into his waistband.

"A more sophisticated person hides it inside a condom and secretes it rather more fully.

"Also there was no charger with it, and there is little value to a phone if you can't charge it up.

"It was a spur-of-the-moment thing and there was no intention to sell the phone, only to contact his partner and girlfriend.

"His family didn't even know about it. There was no sophisticated attempt to conceal it properly, and he had only attended for a pre-sentence report and expected not to go to prison that day."

Sentencing Grifiths to three-and- a-half months in prison, Deputy District Judge William Tate said: "You knew the risk you were taking when you smuggled the phone into prison, as you have been in prison before. It is a serious matter, and the only sentence appropriate is one of immediate imprisonment."

Grifiths, who has two children and is expecting a third, was also sentenced to a further two weeks, to run consecutively, for failing to answer bail in April.