English Heritage has criticised a landowner for removing a First World War structure at the centre of a controversial warehouse plan.

The remains of a 1916 tunnel and surrounding earth mound were removed before the heritage body inspected the site.

Banbury Civic Society called in English Heritage in a bid to legally protect the remains and other war relics on the site.

This could stand in the way of a controversial plan to put six warehouses on the land.

Several small buildings on the site, alongside the M40, were used for hand-filling munitions with explosives during the war.

English Heritage said the site was the last surviving First World War relic of its type in England.

A planning consultant behind the warehouses plan – which could create up to 1,000 jobs – said the demolished structure had been dangerous.

An English Heritage spokesman said: “We are aware of demolition works to the west of the site and it is disappointing that these works are taking place while we are still considering the case.

“However, the demolition of the former filled shell store and the earth embankment around it hasn’t lessened our interest in the site as a whole.”

It said it would soon make a recommendation to the Government on whether the structures should be made a “scheduled monument”.

Banbury Civic Society chairman Rob Kinchin-Smith, below, said: “These are important surviving remains. Removing them when the site is under active consideration for scheduling is not good practice. It leaves a bad taste in the mouth.”

He added that the warehouse plan was “unacceptably intrusive”.

Peter Frampton, the planning consultant for the scheme, said: “Some work has been done by the landowner, which he is entitled to do under permitted development rights.”

He said the removed structure was in a dangerous condition, adding that an original archaeological survey had made reference to the remains but subsequent research had showed them to be more substantial than first thought.

Cherwell District Council is investigating if the demolition is a breach of planning laws and is due to make a decision on June 21.