The Prime Minister has been shown around Britain’s £3 billion aircraft carrier during a blustery visit to the south coast before the vessel’s first operational deployment.

Boris Johnson took the opportunity to tour HMS Queen Elizabeth before the flagship is due to leave for the Far East on Saturday evening.

The departure has been brought forward by the Royal Navy due to heavy winds forecast for the weekend.

During his visit to Portsmouth on Friday, Mr Johnson faced strong winds as he inspected the flight deck of the aircraft carrier.

In calmer conditions, he also spoke to bridge crew and experienced what it is like to sit in the cockpit of an Lockheed Martin F-35 Lightning II plane.

Speaking to broadcasters, the PM said the deployment of the 280-metre ship to the Far East would not be “confrontational”, but was instead about asserting the “international law of the sea”.

The trip comes after the UK Government’s Integrated Review of defence and foreign policy decided Britain should “tilt” its focus towards the Indo-Pacific region, seen as a response to the growing influence of China on the world stage.

Mr Johnson said: “This is an opportunity to work with friends and partners around the world, about 40 countries will be joining us on this on this operation.

“This Carrier Strike Group will be going through Suez, through the Red Sea, round India, through the south China seas.

“And on the way, the people who will be going on this mission will be doing a number of things – they’ll be projecting not just Britain’s hard power, military capabilities, which are obviously extraordinary, but also our soft power, our values, what we stand for, our belief in democracy, in the rule of law.

“One of the things we’ll be doing clearly is showing to our friends in China that we believe in the international law of the sea and, in a confident but not a confrontational way, we will be vindicating that point.”

Asked whether it was designed to provoke Beijing, Mr Johnson replied: “No, we don’t want to antagonise anybody.”

The 65,000-tonne warship had intended to depart on Sunday morning but bad weather forced the navy to change its plan, and it is now expected to leave on Saturday night.

It will be the first time the carrier has left the port at night, although it has sailed into Portsmouth in the early hours previously.

A Ministry of Defence spokesman explained that winds had to be taken into account because of the narrow entrance of Portsmouth Harbour as well as the dredged channels for the approaches from the Solent which were created specifically for the carriers.

He said: “This is a standard response to a changing weather system.”

The carrier, with eight RAF and 10 US Marine Corps F35B stealth fighter jets on board, will depart for Asia accompanied by six Royal Navy ships, a submarine, 14 naval helicopters and a company of Royal Marines.

The Carrier Strike Group, which will carry out visits to India, Japan, South Korea and Singapore, will include the US destroyer USS The Sullivans and the Dutch frigate HNLMS Evertsen.

A total of 3,700 sailors, aviators and marines are involved in the deployment which will cover 25,000 nautical miles.