Police would not reveal the locations, but one of the three Newbury homes targeted is believed to be in Greenham.

Similar raids happened across the country, after an undercover intelligence operation, and of the 14 addresses searched in the Thames Valley, seven arrests were made, including two in Newbury.

The commander of Operation Hostage, Supt Graham Bell, said: "Possession of these weapons is illegal under the Firearms Act and this morning's operation shows that we will take a robust approach to those people who have them. The information provided to us by NCIS is fairly conclusive and revolves around purchase of these items from a web-site that is based elsewhere in Europe".

"We are committed to keeping these weapons off the streets. I would like to re-assure the public that we will act quickly and decisively whenever we receive information about the illegal possession of such items".

Drugs, other weapons, computers, and suspect goods were also seized in the raids, which saw 50 officers armed with warrants enter the houses, stretching from Milton Keynes to Newbury.