Over the last month, the bulk of Iran’s fleet of oil supertankers suddenly disappeared off the map. When they re-emerged on the high seas, the freshly painted tankers had new names, new flags and new home ports.

The ships’ new identities – changed, for example, from Hoda, Honar and Nesa to Precious, Victory and Truth – is the latest episode in a cat-and-mouse game between Tehran and western officials tracking Iranian oil exports.

Since the beginning of the year, Tehran has tried to hide the final destination of its oil exports as western powers have targeted its energy sales in an effort to bring Iran to the negotiating table over its nuclear programme. While the name changing does not stop trackers finding the vessels, it complicates their efforts.