DETECTIVES have released a CCTV image of a man they believe is responsible for a string of frightening knifepoint robberies across Poole.

Police, who say he threatened shocked victims with a knife on four separate occasions in just over 24-hours, are appealing for help to track the armed robber down.

No-one was injured in any of the incidents, officers have confirmed.

He first targeted the convenience store Jas News & Booze, Poole Road, around 10.35pm on Sunday.

Staff said he picked up a carton of milk before approaching the counter, pulling out a knife and demanding money from the till.

He escaped with a quantity of cash.

Then, at 9.05pm on Monday evening he fled empty-handed after demanding money at knifepoint from staff at the Shell Service Station on Bournemouth Road.

Forty minutes later at Tatnum off-licence, Tatnum Crescent, he once again fled empty-handed after an alarm was activated. He'd brandished a knife and demanded the contents of the till.

Then, at 11.20pm later that night, a taxi driver who had just dropped off a passenger in the car park at The Adam Practice, Longfleet Road, was approached and threatened with a knife. This time he ran off with cash stolen from the cabbie.

Detective Inspector Steve Symms, of Poole and Bournemouth CID, said: "I am now able to release a CCTV image of the suspect and after initial investigations we now believe all four incidents to be linked to the same man.

"These were frightening incidents for all the victims involved and I am appealing to the public to help identify the person pictured."

A nearby resident reported lots of police activity on the forecourt area of the Shell Service Station, until well after 10pm.

One local woman, who asked not to be named, said: "I was told this morning by my boss that they'd been an attempted robbery at the petrol station.

"I didn't see anything though I'm afraid. I just hope everyone is OK and they catch whoever is responsible soon. It cannot be nice to be on the other end of something like that."

The suspect is white, slim build, around five feet seven inches. He wore a light grey hooded jacket and dark sunglasses.

Detective Inspector Symms added: "Anyone who may have witnesses a man matching this description in the areas at the time of any of the incidents or has further information should contact Dorset Police in confidence on 101."