HMS Queen Elizabeth is edging ever-closer to being an operational warship after the powering up of one of her huge diesel generators.
The future flagship of the Royal Navy has four such power units, each weighing around 200 tonnes and providing enough energy to power the vessel at cruise speeds.
At full-speed two Gas Turbines also come into play. Working together the plant will be able to produce enough energy to power a medium-sized town.
Defence Minister Philip Dunne MP was the first to get his hands on the keys and was keen to stress the importance of the development.
"Powering up the diesel generator today marks an important milestone on the journey to bring these highly versatile ships into service with our Armed Forces.
"They will be the largest, most capable and effective surface warships ever constructed in the UK."
Sea trials with the 65,000 tonne HMS Queen Elizabeth are scheduled to begin in 2017 followed by flying trials with helicopters and the F-35B Lightning II starting in 2018.
A second carrier, HMS Prince Of Wales, is almost half built and is scheduled to enter service in 2023.