POOLE town centre was brought to a standstill yesterday evening by its third major "bomb" scare in 15 months after a workman found explosives near a busy supermarket.

The man used his mobile phone to report the potentially deadly discovery to the police. He, and his three colleagues, had to stop work and a 100-metre exclusion zone was put in place.

The drama began to unfold at about 3.30pm on land between the new Asda and the Royal National Lifeboat Institution headquarters in West Quay Road.

Cars were stopped from going into the supermarket car park and the Poole lifting bridge was closed to stop boats passing the danger zone.

Dorset fire and rescue and ambulance crews were placed on standby and Army bomb disposal experts were called in from Wiltshire to examine the find, reported by police as a 30cm stick of dynamite.

As the rush-hour traffic died down, police sealed off the area to traffic and evacuated Asda and nearby buildings. Seldown Bridge, the Holes Bay Road dual carriageway and West Quay Road were closed so that a controlled explosion could be carried out.

An eyewitness, who asked not to be named, said: "There was no sign of panic. I was shopping with my wife and we were told to leave the supermarket. The police seemed to be doing a good job controlling the people and traffic because it could have been chaos."

In July last year, a digger working on the Asda site struck a World War One phosphorus grenade, releasing fumes into the air and causing a fire.

Eight more of the grenades were later found at the spot, previously occupied by agricultural feed suppliers Dalgety.

Days later, a further grenade was found as workers continued clearing the site. The area once more evacuated and Holes Bay Road closed while a controlled explosion was carried out.

In July this year, a large section of the town centre was evacuated after two suspect packages were found at Poole railway station just hours after four terrorist bombs killed bus and Tube passengers in London.