The fireworks are banned in this country because they are "unstable"

The three-and-a-half tonne haul was found inside a lorry trailer aboard a cargo ship on Wednesday.

Customs and Excise officers believe the fireworks, which are sold in parts of the Far East, were destined for the black market.

Spokesman Mike Connolly told BBC Look North the banned products would have been "time bombs" out on the streets.

He said: "These are black market fireworks and are not legal.

"They are stronger, do not have a licence and have no health warnings - they are absolute time bombs."

Customs challenge

All four types of the fireworks found are banned in this country because of their unstable nature.

But Mr Connolly admitted they were unlikely to find the culprits.

"These people are organised in what they are doing," he added.

"They are falsifying paper work and it's a very difficult job for us - but at least we've stopped these getting on to the streets."

The fireworks will be catalogued and sent for destruction while the customs investigation continues.