The fireworks were being stored on unlicensed premises

Fire and police officers acted after a tip-off that the fireworks were being stored at a scrap yard in Boulder Bridge Lane, Carlton, Barnsley.

The raid was part of Operation Mischief which was launched this week to combat anti-social behaviour and specifically the misuse of fireworks.

The huge haul includes three-feet high rockets and other fireworks usually used in organised public displays.

That's a significant seizure when you think that a shipping container takes about 15 tons Mark Shaw, South Yorkshire Fire Service

Pornographic DVDs, counterfeit clothing, 40,000 cigarettes and more than 300 bottles of whisky and wine were also recovered.

Officers are still trying to establish whether or not the fireworks meet British manufacturing standards, but say the premises was unlicensed to store them.

No arrests have been made.

Divisional officer Mark Shaw, of South Yorkshire Fire Service, said: "We found about seven tons of fireworks.

"That's a significant seizure when you think that a shipping container takes about 15 tonnes.

"I am sure there will be more out there, but the public can be sure we will enforce the law vigorously."

Officials from Customs and Excise, Trading Standards and the Inland Revenue also took part in the raid on Friday.

A police spokeswoman said: "This was a collaborative effort and part of the multi-agency Operation Mischief to combat antisocial behaviour in South Yorkshire."