Britain’s armed forces are planning for potential military action against Iran triggered by increasing concerns over its nuclear enrichment programme.

The UK’s Ministry of Defence says the US may choose to carry out missile strikes at some key Iranian facilities. If Washington decides to do this, it will seek and receive UK military assistance.

British military planners are discussing where to deploy Royal Navy ships and submarines equipped with Tomahawk cruise missiles over the coming months as part of an air and sea campaign. The US might also ask permission to launch attacks from Diego Garcia, British territory in the Indian Ocean.

“The British government believes that a dual track strategy of pressure and engagement is the best approach to address the threat from Iran’s nuclear programme and avoid regional conflict,” says a spokesman for the Ministry of Defence. “We want a negotiated solution, but all options should be kept on the table.”

The UN nuclear watchdog, the International Atomic Energy Agency (IAEA) will release a report next week showing Iran is carrying out a nuclear weapons programme, as well as its civilian energy ambitions.

Government ministers have been told that Iranians have been moving some more efficient centrifuges into the heavily-fortified military base under a mountain near the city of Qom. The centrifuges can be used to enrich uranium for use in weapons and are so protected in the base, missile strikes might be unable to reach them.