Europe is studying proposals that may allow the charging of navigational fees in the strait of Hormuz so long as the tolls are not compulsory and have the support of the UN agency that regulates maritime transport.

Britain’s deputy prime minister, David Lammy, said the imposition of compulsory tolls would be disastrous. But some of his cabinet colleagues said they recognised that systems of payments for specific navigational services were permissible in many natural waterways, including the strait of Malacca and the Channel.

It comes as US officials demanded Iran make a public statement saying the strait of Hormuz is open and that ships using the vital corridor won’t be attacked any more. The US officials blamed power struggles inside Tehran for the difficulty in reaching and adhering to a deal.