Bus drivers are to be quizzed on ways to step up security following the third attack in less than a fortnight.

The latest happened on Sunday at 11.30pm when an empty bus broke down in Queen's Park Road, Brighton.

The driver was waiting for a mechanic when the offender climbed on board, threatened him with a knife and escaped with a small amount of cash.

Police think the offender may be the same man who robbed the driver of a No 7 service in Donald Hall Road, Brighton, last Thursday.

A knife was used in that robbery and again the offender escaped with cash.

The driver and three passengers suffered shock but were unhurt.

Another driver had cash stolen less than two weeks ago but police are not connecting the crime.

It happened in Swanborough Drive, Whitehawk, Brighton, when two men grabbed a cash bag while the driver was distracted. CCTV footage of the men has been handed to police.

One angry driver told The Argus: "It's no good spending money on CCTV. We should have security screens to protect us.

"If nothing happens then we'll pull buses off the streets at night."

But GMB union representative Gary Smith said there were no plans among drivers to take action and there was "no enthusiasm" to install security screens.

He said: "A lot of drivers don't like them because they make them feel claustrophobic."

He said the union and Brighton and Hove Bus and Coach Company was planning a survey among drivers on violence at work to look for new security measures.

He said he would like to see tougher action by police and the courts.

His view was echoed by the bus company's managing director, Roger French.

He said: "These robberies are deplorable and I hope the courts deal severely with those responsible.

"We can't have our drivers facing this kind of threat."

He agreed many drivers were opposed to security screens, saying: "They have been installed on buses in London but the number of robberies has gone up."

Sergeant Steve French, of Brighton police, said: "We are working closely with the bus company with a view to them installing cameras on more of their buses and on ways to improve security of money on buses."

Police are appealing for witnesses to the robberies to come forward.