RFA Tidespring carrying out a fuel replenishment at sea during the Carrier Strike Group 21 deployment (Picture: Royal Navy).

What speedbumps did the Carrier Strike Group face?

RFA Tidespring carrying out a fuel replenishment at sea during the Carrier Strike Group 21 deployment (Picture: Royal Navy).

The UK’s flagship and an entourage of other vessels have returned to the UK following the landmark Carrier Strike Group (CSG) mission.

Escorted around the world by warships from the Royal Navy and allies, HMS Queen Elizabeth's (HMSQE) maiden deployment saw collective visits and engagement with more than 40 nations as part of 'Global Britain's' Indo-Pacific tilt.

Returning home, the CSG Commander, Commodore Steve Moorhouse, posted a social video message detailing a "complex" and "challenging" journey, despite its successes.

The first and most notable incident for the formation was the loss of a £88.8m F-35 fighter jet at sea, although the pilot survived.

Its wreckage has since been recovered, after a leaked video of an aircraft dropping close to the flight deck of HMSQE and what some experts feared could have been a race with Russia to find it.

Earlier in the voyage, Type 45 destroyer HMS Defender was involved in a stand-off with the Russian navy after it sailed close to Crimea in June.

The Kremlin claimed warning shots were fired by Russian vessels at the ship as it passed through the contested part of the Black Sea – an assertion dismissed by the UK Government, which said only that a routine "gunnery exercise" took place.

Watch: Dambusters Squadron F-35s leave HMS Queen Elizabeth.

Forces News was first to report on Russian fighter and bomber "air incursions and overflight" which forced more than 30 live interceptions by the UK in just over two weeks – orchestrated by HMSQE in the Mediterranean.

Speaking in October, Cdre Moorhouse said the CSG group was "launching the first F-35 sorties, from the Mediterranean, north into the Black Sea – a round trip of well over 1,000 miles, whilst also sending jets east into Iraq and Syria, on six and seven-hour missions in support of Operation Shader".

"Throughout, we were maintaining an on-deck ready alert capability to respond to Russian air incursions and overflight," he said.

"Was this all needed? Was it necessary? Yes, it was."

Watch: Is this the moment a British F-35B crashed?

In July, HMS Duncan suffered a mechanical issue with its engine, forcing it to undergo repairs before returning to the CSG six weeks later.

In the same month, a number of Strike Group vessels, including HMSQE, experienced a COVID-19 outbreak despite all the crew being double-vaccinated.

A sailor on board the Type 23 frigate HMS Kent was also confirmed to have died in July. An investigation has been launched.

Leading from the front during the 25,000-nautical mile round trip, HMSQE had originally been expected to return to Portsmouth on 10 December, but the arrival was brought forward by a day because of concerns about the weather.

A narrow entrance to Portsmouth Harbour means that the 65,000-tonne warship would not routinely enter during heavy winds.