The Royal Navy's new 3-billion-pound Aircraft carrier HMS Queen Elizabeth is leaking.
The Navy's future flagship is taking on hundreds of litres of seawater because of a fault with one of the seals around its propeller shafts.
The fault on the £3.1bn carrier was first identified during sea trials.
However, a Royal Navy spokesperson said the ship is scheduled for repair and the fault will not prevent her from sailing again early in the new year.
The warship was only accepted into the Royal Navy fleet by The Queen earlier this month.
And repairs will not cost the British taxpayer a penny, the Defence Secretary has insisted.
Pressed on suggestions that repairs could cost millions, Gavin Williamson told the Press Association the money would come "from the contractors who built her".
"This isn't going to cost the British taxpayer a penny," he said.
The vessel, 919ft (280m) long and with an estimated working life of half a century, is understood to have been leaking for some time.
Mr Williamson went on:
"This is the reason why we have the sea trials, to make sure that everything is working absolutely perfectly.
"This is something that work is currently ongoing to deal with, and HMS Queen Elizabeth will be going out early on in the new year to continue her sea trials and making sure she is fully operable in terms of helicopters and the F-35 being able to fly off her deck.
"HMS Queen Elizabeth is the most magnificent aircraft carrier in the world and, when she is fully operational and she is being deployed right around the world, she is going to make a significant difference as to what we can actually achieve and what we are able to do as a global power."
At 280m long and with an estimated half-a-century working life, the behemoth is the biggest and most powerful ever built by the UK.
It is understood the vessel has been leaking for some time.
A Royal Navy spokesman said:
"An issue with a shaft seal has been identified during HMS Queen Elizabeth's sea trials; this is scheduled for repair while she is alongside at Portsmouth.
"It does not prevent her from sailing again and her sea trials programme will not be affected."
The aircraft carrier weighs 65,000 tonnes and has a top speed in excess of 25 knots.
A number of ship-building yards around the country were involved in the build, including Govan and Scotstoun in Glasgow, Appledore in Devon, Cammell Laird in Liverpool, A&P on the Tyne in Newcastle and Portsmouth.
Around 10,000 people worked on the construction of the ship.