Last month, Carlos Del Toro, the US navy secretary, warned that “given the near-term threats to the UK and US”, investments in the Royal Navy were “significantly important”.
Tobias Ellwood, former chairman of the defence select committee, said: “When advances in missile technology saw the phasing out of battleships with those mighty 16in guns that could strike targets at sea and on land, the Navy prioritised blue-water warfare, focusing only on defending against and striking air, surface and subsurface targets.
“It is now clear the UK should have followed the example of the US and fitted the Type 45s with Tomahawks rather than only placing them in our submarine fleet.”
Mr Ellwood has since written to the Defence Secretary recommending “consideration of short-term solutions for our destroyer fleet”, including adapting the latest model of guided multiple launch rocket system launchers.
“In the meantime we should immediately dispatch our carrier group armed with F-35s,” he added. “This is what it was built for.”
A defence source defended the installation of the gyms, saying that “space in any warship is at a premium” and that “available space is often used to house gym equipment that can easily be removed should that area be required for operational use”.
Dr Phil Weir, a naval historian, said there had been a view that land attack was covered by nuclear attack submarines, so surface ships did not require them.
“The submarines can’t be everywhere,” he added.
“They also have other jobs to do in terms of things like intelligence gathering, so that’s not always conducive to popping up and firing missiles.
“This was an attitude we could get away with back in the glory days of early 2000s when there didn’t seem to be as much of a submarine threat from Russia.
“But with the uptick from Russia and increasing threat from China you need to develop other options.”
Pete Sandeman, director of Navy Lookout, said: “For years, many commentators and naval advocates have urged the Navy to add land attack capability to its surface ships.
“For the majority of other top-tier navies this is a standard feature of major surface combatants.
“Over the last 20 years, wars in Iraq and Afghanistan, together with prioritisation of the carriers and assorted other pressures, have left this as an unfunded aspiration.
“Only with increased likelihood of peer conflict recognised in the last five years or so, has the Navy very slowly started to address its lack of offensive weaponry.”
A Ministry of Defence spokesman said: “The Type 45 destroyers are optimised for air defence and this capability is due to be further enhanced by the incorporation of the common anti-air modular missile.”