Residents and workers were evacuated from a Watford road this morning after a bomb disposal team was called to an industrial park.

A bomb disposal squad was called to Wiggenhall Road at 8.37am and police confirmed a 'disused mortar' had been discovered.

Sean Newstead, 25, Manager of Skyline Roofing, which is based on the Wiggenhall Industrial Estate said: "I was sitting at my desk when suddenly a couple of police officers were standing next to me.

"I asked them what was going on but they told me I needed to count up all the people in the building and get everyone out immediately. Police evacuated everyone else on the industrial estate.

"We all had to wait at the BP petrol station at the top of the road and everyone was confused. No one was allowed to enter the industrial estate - they locked all the gates - and no one told us what was happening.

"After half an hour we saw a bomb disposal team and everyone was surprised that this was happening.

Mr Newstead and his team were allowed back into their building after an hour, and later found the incident was not as serious as first thought.

Watford’s Police Commander, Superintendent Sue Jameson said: "It was a disused mortar.

"There’s a disused railway line nearby and we understand, historically, that mortars were set off to alert drivers to hazards. We believe it was one of those mortars, but our investigation is still ongoing and won’t know for certain until that has been completed.

"We would like to apologise to anyone affected by the disruption but we had to be sure and we had to be careful."

Hertfordshire Constabulary has issued the following advice to anyone who may discover a suspected explosive device.

• Do not touch the item or device or attempt to move it any way.

• People should not use a mobile phone or any other electronic devices near the item, and people should contact the police by dialling 999.

• Trained staff will then be able to offer advice on what action to take next while officers are sent to the scene.