A cleaner triggered an emergency evacuation when he made a hoax bomb call to the bank where he worked.

Peter Heming, 57, attempted to disguise his voice with a fake West Country accent when he rang HSBC's Worthing office on his mobile phone one evening in June.

A shocked security officer heard a voice saying: "That's the last time you stitch me up, you buggers, I have put a bomb in the building."

Heming's plot was rumbled when the officer recognised his voice and police later traced the call to his phone.

A jury yesterday took just under three hours to convict him of making a false communication with intent to make someone believe there was a bomb in the building.

Heming, of The Quadrant, Goring, was cleared of a similar charge relating to a second hoax call one evening in July, which was also traced to his phone.

Prosecutor Clare Huntley told a two-day trial at Chichester Crown Court: "He was working for a contracted company, which HSBC employed to undertake cleaning of that branch.

"The prosecution say Mr Heming made two calls to the branch.

"The first call was made on June 24, 2002, and was answered by Jeremy Bundell. He received words he perceived to be a bomb warning.

"The second call was made on July 1, 2002, and on the same number and was answered by Sukinda Arora.

"He perceived the information to be a bomb threat and the police were called."

Investigations showed both calls had been made on Heming's mobile telephone.

Miss Huntley said: "He admits those phone records and admits the calls were made from his phone. He doesn't admit that he made the calls."

She said Heming told police when he was working he would leave his mobile phone either in his car or in a cabinet so someone else must have made the calls.

Mr Bendell, a security officer for HSBC, said: "My initial reaction was I recognised the voice.

"It was a male voice. It seemed like a fake West Country accent. I thought it was a member of our cleaning staff, Peter Heming."

In a statement read to the court his colleague Mr Arora, who has since died, said of the second call: "I picked up the receiver. I said hello. A male voice replied 'I used to work here and there is a bomb in the building and it is going to explode at 7.30pm'."

Judge Charles Byers adjourned the case until August 29 for pre-sentence reports to be prepared.

He warned Heming: "I'm giving you no indication of how I shall deal with this matter, only to say the courts deal with this sort of thing in a very serious manner."