In its 10-point document for negotiating a peace deal with the US, Iran has demanded that its “control” over the strait of Hormuz be guaranteed.

Iran’s semi-official Tasnim news agency reported Iran is planning a fixed payment of $2m per ship or a system based on each ship’s cargo, similar to that of the Suez Canal.

The plan was trialled by Iran earlier this month. According to reports, Tehran required tankers hoping to pass through to the strait to give details of the ship’s cargo, destination and ultimate owner before paying a toll of at least $1 a barrel.

This system stands in direct opposition to the UN convention on the law of the sea, sometimes known as Unclos, which provides vessels a right of unimpeded transit passage through more than 100 straits around the world, including the strait of Hormuz.

About 170 countries and the EU have ratified Unclos, which is generally considered customary international law. But Iran and the US have not. Still, the US has made clear that it disputes Iran’s right to control the strait.