French customs officials say they have seized a record haul of four-hundred-thousand ecstasy tablets together with large quantities of other drugs on a lorry bound for Britain.

The drugs, which have an estimated street value of nearly ten-million dollars, were found during a routine check near the northern French port of Dunkirk.

Customs officials say tests showed that most of the ecstasy tablets were a new and much more powerful version of the drug, which had effects similar to the hallucinogenic drug LSD.

The truck driver, who is British, has been taken into custody.