A Norfolk town centre has returned to normal after shop staff and pedestrians were evacuated following reports a suspicious package had been found at a Royal Mail delivery office.

Explosive Ordnance Disposal officers from the MOD attended the incident at the delivery office in Market Place, Diss this lunchtime and confirmed the package was a genuine parcel.

Police moved hundreds of people away from the vicinity of the delivery office at 9.30am, with a police exclusion zone being set up at the junction of Mere Street and Chapel Street, outside the tourist information centre.

Jason Beeton, manager of the Boots store in Market Place, said a customer had said the Post Office had been closed because of a suspected bomb, but he did not pay too much attention to it until he heard something official from the police.

However, when he saw the road being closed off outside he approached one of the police officers who told him there had been a 'credible threat' and he would need to evacuate with his staff.

He said: 'The evacuation was relatively straightforward. There were a lot of people that were perhaps a bit confused, but otherwise it was all fairly orderly. The police did not give us any details of what it was, just that it was a credible threat and we needed to get a safe distance away.'

Another evacuee David Bracegirdle, manager of Carphone Warehouse, said police officers came into his shop and told staff they needed to evacuate.

He said: 'There was no great panic really, people were just ambling away from the scene. There was no great rush at all.'

He said his shop had been doing reasonable trade in the morning and the town centre had been fairly busy.

Sarah Green, manager of a Co-Op store two doors down from the Post Office, said people were a bit confused during the evacuation, adding: 'Diss is a small market town and you don't really expect something to happen here.'

Royal Mail spokesman Sally Hopkins said: 'We can confirm that a suspect item was found in Diss delivery office this morning and on the advice of the police the building was evacuated and an exclusion zone was set up around the site. We apologise to any customers who could not access the enquiry office, which was closed for a short while.

'The package was found to be harmless so the exclusion zone has now been lifted and the enquiry office will re-open as usual this afternoon at 2pm. There was no disruption to deliveries, which went out this morning as usual. Mail collections will be made this evening as usual.'