A defence minister has revealed that just one out of the Royal Navy's six Type 45 destroyers is operationally available, with the rest either undergoing maintenance or being fixed.
Royal Navy warship HMS Defender is, at the moment, the only Type 45 on operations.
HMS Diamond has experienced some technical issues and has detached from CSG21 for maintenance, inspection and defect rectification.
HMS Daring and HMS Duncan are currently undergoing planned deep maintenance.
While HMS Dauntless, the first of the Type 45 destroyers to undergo a Power Improvement Project (PIP) upgrade, is expected to return to sea for trials this year.
HMS Dragon is undergoing a period of planned maintenance in advance of further operational commitments.
Commons Defence Committee chairman Tobias Ellwood suggested the situation was "operationally unacceptable".
Defence Procurement Minister Jeremy Quin told MPs on the committee: "We have two Type 45s embarked with the CSG, Diamond has got current issues but I hope they will be able to be rectified shortly."
Mr Ellwood said: "HMS Defender is now our only current operational Type 45.
"If that ship experiences propulsion problems as we have seen across the Type 45 family, then our carrier group would have to be forced to lean on a NATO ally to ensure that we have destroyer protection.
"That really indicates – bottom line – we need a bigger Navy."
What are the Royal Navy's Type 45 destroyers?
The Type 45 destroyers are among the most advanced in the Royal Navy fleet, capable of carrying out a range of operations, including defence from air attack, counter-piracy and humanitarian aid.
With huge potential in both combat and non-combat roles, the vessels are already a distinguishable symbol of UK strength as Britain strives toward a more global presence.
Equipped with the Sea Viper missile system, capable of hitting airborne, moving targets from 70 miles away, the vessels will form an important component within the UK Carrier Strike Groups of the future.
Earlier this month, it was announced the vessels will receive a £500m upgrade to their firepower capability which will see the warships' missile capacity increased by 50%.
Cover image: HMS Daring captured from C-130J Hercules supporting the Carrier Strike Group (Picture: MOD Crown Copyright).