Army units yesterday closed a St Albans road to help with an incident overseen by the Ministry of Defence.

Woodcock Hill in Sandridge, at the junction with House Lane and Nashes Farm Lane, was shut and a witness said he saw “bomb squad” vans in the area.

A Home Office spokesperson said: “Following a routine audit at the Centre for Applied Science and Technology, concern was raised about a very small amount of material stored on site and it was decided to seek the assistance of Explosive Ordnance Disposal (EOD) as a precautionary measure.

“The site was evacuated and a controlled explosion was carried out. No people or property were placed at risk and no damage was caused by this action.”

Herts police said: “Police were called to a premises in Woodcock Hill in Sandridge at 10.55am to request assistance in disposing of items which were found within the location.

“Officers liaised with Explosive Ordnance Disposal (EOD) who advised a 100 metre cordon be put in place and as a precaution people were evacuated from the building.

“Items were removed by the EOD to a nearby field and a controlled explosion was carried out.

“The matter was dealt with by 3.50pm.

“We don’t have any details on our log as to exactly what the items were.”