More than 100 children were evacuated from their school after a Second World War bomb was discovered.

A 400-metre exclusion zone was placed around the southern storage area at the Harwell International Business Centre where the bomb was found at 2pm yesterday.

Chilton Primary School, the Horse and Jockey Guest House, 12 homes in Severn Road and Upper Farm in Chilton were evacuated while munitions experts from the military's explosive ordnance disposal team examined the device.

The alert was eventually called off at 6pm when it was discovered that the device had actually been made safe and there was no risk of explosion.

The cordon was lifted and residents were allowed to return to their homes. The Horse and Jockey pub and the Chilton Garden Centre opened for business once again.

Chilton primary's chairman of governors Colin Hills said emergency arrangements had been in place to evacuate the children.

"I'm very pleased that the process that was set up has gone very smoothly," he said.

The bomb was found outside the Harwell security fence on land that was formerly part of the RAF Harwell air field. The site is currently being cleared of chemical and military waste as part of the United Kingdom Atomic Energy Authority's (UKAEA) programme to restore the environment.

Yesterday's bomb scare came two weeks after five controlled explosions were carried out at the site to detonate war-time practice bombs and flares uncovered by the clean up.