Britain's dwindling Navy fleet means the country will be unable to deal with international threats in future unless urgent action is taken, MPs have warned.

In a report called Restoring The Fleet, published by the defence select committee on Monday (21 November), MPs raised concerns it would be "completely unacceptable" if the fleet dropped below its present 19 frigates.

Committee chairman Julian Lewis said the fleet is already below the critical number needed and sounded the alarm as one frigate per year will leave service between 2023 and 2035.

"What remains of our surface fleet now faces a prolonged period of uncertainty, as the frigate class is replaced in its entirety and all our destroyers undergo urgent, major remedial work on their unreliable engines," The Times reported.

The committee urged for plans to be put in place to replace 13 ageing Type 23 frigates with new models.

Earlier in November, Defence Secretary Michael Fallon announced the Government would commit to building eight new Type 26 global combat ships but has not committed to five general purpose frigates and there has been no finalised contract between the Ministry of Defence (MoD) and BAE.

The report also said that the MoD had made "extraordinary mistakes" in the design of six Type 45 destroyers, which cost £1bn each.

The report criticised the MoD and BAE Systems, accusing the department and contractors of a "serious failing" for under-testing the system, which is unable to operate continuously in warm waters.

"It is astonishing that the specification for the Type 45 did not include the requirement for the ships to operate at full capacity — and for sustained periods — in hot regions such as the Gulf," the committee said.

"The UK's enduring presence in the Gulf should have made it a key requirement for the engines. The fact that it was not was an inexcusable failing and one which must not be repeated."

An MoD spokesperson said: "We are investing in a growing Royal Navy by building two aircraft carriers, the new Type 26 global combat ship, dreadnought and astute class submarines, and offshore patrols vessels.

"We are also developing new class of lighter general purpose frigate so that by the 2030s we can grow the size of the fleet.

"This major programme of investment will ensure that the Royal Navy remains one of the world's most modern and powerful navies with a genuine global reach," Sky News reported.