Six men have been arrested after heroin worth an estimated £5.6m was seized in a warehouse raid in east London.
About 80 kilos of the Class A drug was discovered hidden in a lorry carrying charcoal at the business in Walthamstow.
The arrested men - three Romanians, one Turkish Cypriot and two Britons - are in custody at an unnamed location while inquiries continue.
Up to 60 customs officers took part in the operation.
Steve Coates, customs assistant chief investigation officer, said: "This Customs intelligence-led operation has stopped a substantial amount of heroin from reaching the streets of the UK."