The UK's National Crime Agency has recorded its largest-ever heroin bust off a Maersk boxship.

Law enforcement said Wednesday that it tracked nearly 1.3 tonnes of the drug — street value £120m ($164.2m) — from Felixstowe to Rotterdam after the ship dropped anchor in the UK 30 August.

The National Crime Agency (NCA) did not name the owner of the ship, but maritime security firm Gray Page identified it as the 10,100-teu Maersk Gibraltar (built 2012).