Mahir Kaynar, 36, of Barnet, north London, received 40 years and Ali Osman Gok, 28, of Edmonton, also north London, was sentenced to 30 years after being found guilty of conspiring with others to supply heroin on 8 August last year.

A third defendant - who cannot be named for legal reasons - may face retrial after the jury was unable to reach a decision in his case.

That ruling will be announced on 13 November.

Sentencing, Judge Jarlath Finney said Kaynar and Gok had been responsible for a "despicable" plan to flood the streets with hard drugs.

157kg of brown powder

Wood Green Crown Court in north London heard that the heroin was smuggled into the country in the adapted fuel tank compartment of a lorry.

John Hardy, prosecuting, said it was "one of the most substantial quantities of heroin seized by police on the UK mainland".

Had it been broken down to individual portions for heroin users to take and sold at street level it would have been worth about £30 million.

Police examined 12 recovered packages and found them to contain 157kg of a brown powder that contained heroin.

Kaynar and Gok said they did not know the lorry contained heroin.