Thousands of canisters of nitrous oxide have been uncovered by police responding to a crash on the M6.
The collision involved two vehicles near Corley Services in Warwickshire on Tuesday afternoon.
Police said the smell of cannabis prompted officers to search a car. Inside they found 6,000 canisters, cannabis and other paraphernalia.
A 24-year-old man has been arrested on suspicion of possession of drugs with intent to supply.
A further warrant carried out at a Birmingham storage unit revealed 15,000 canisters of nitrous oxide.