Bomb disposal experts evacuated a police headquarters when they feared hoax devices collected by officers might explode.

The bomb squad had arrived at Centenary House in Durrington Lane, Worthing, to collect inert explosives stored in an outdoor pit but when they spotted the 20 metal cylinders with matches taped to them they evacuated the building.

More than 100 people were forced to wait outside Centenary House for almost two hours from 2pm yesterday.

Experts X-rayed the cylinders and they were declared safe. Council staff and police staff were then allowed back inside the building.

The fake bombs had been placed in the pit after they were seized from a house in Yapton, near Littlehampton, on June 21.

The 20 5in-long cylinders, used to fire paintballs, were found when police arrested a man believed to be responsible for throwing a flash flare into Bognor police station.

Chief Inspector Sharon Rowe said the cylinders were initially declared safe by the force's firearms officers.

The bomb disposal team decided to double-check and evacuated the building, which houses the town's police headquarters and West Sussex County Council's education, trading standards and social services departments. Residents living nearby were told to stay indoors.

Chief Insp Rowe said: "We made an assessment at the time of arresting the man. The risk was leaving them at the property if we had a suspicion they might explode. Officers put the cylinders in a plastic bag and they were declared safe by firearms officers.

"The bomb squad was not happy and we took their advice to evacuate the building.

"The message to the public is, if you see something suspicious then get out the way, leave it there and telephone the police."

A 40-year-old man has been bailed in connection with the flash flare incident.