The Royal Air Force welcomed the first of its new P-8A Poseidon maritime patrol aircraft to RAF Lossiemouth last month.
The 'City of Elgin' touched down at the base in Scotland on 13 October.
It was then followed by two more of the aircraft, the Pride of Moray and Terence Bulloch, on 14 October.
The fourth P-8A Poseidon arrived at Lossiemouth from the US earlier in the month.
The RAF airfield in Moray has been undergoing an upgrade costing more than £400m in total ahead of the arrival of the Poseidon fleet.
It took two years to build and can hold up to three of the Royal Air Force's eventual nine P-8A Poseidon aircraft.
It is more than 33,000 square metres in size and has training and mission support facilities, including advanced simulators, as well as accommodation for two squadrons.
Until recently, the aircraft had been based at Kinloss, a British Army barracks 12 miles along the coast, which was formerly a Royal Air Force site.
The role of Poseidon
P-8As are equipped with sensors and weapons systems designed for anti-submarine warfare, and will also carry out surveillance and search and rescue missions, according to the RAF.
They fill the role left by the RAF's previous maritime patrol aircraft, the Nimrod, which was retired in 2010.
Based on the Boeing 737-800 airliner, the contract to develop the P-8A for the United States military was granted in 2004, and the first Poseidon flew in 2009.
The US Navy began operating the P-8A in 2013 and variations of the aircraft are in service with the Indian Navy and the Royal Australian Air Force.
The RAF received its first P-8A last October during a ceremony in the United States.
The aircraft is equipped with a range of search and tracking systems, including:
- An APY-10 radar providing high-resolution mapping.
- An acoustic sensor system.
- An IR turret and electronic support measures (ESM).
It also carries torpedoes.
Defence analyst Tim Ripley, from Jane's Defence Weekly, told Forces News earlier in the year: "For 10 years, the RAF has not had a maritime patrol aircraft so this is a major development.
"It is a different type of maritime patrol aircraft. It's not built in the way that the Royal Air Force has operated maritime patrol aircraft in the past.
"It's a converted airliner, so it's not designed to operate at a low level, which is the way that previous generations of British maritime patrol aircraft have operated," he added.
"It was supposed to have a suite of high-level weapons and sonobuoys that could be dropped from a high level – so far, the US Navy has not brought those systems into service.
"So, we have to wait and see how good the P-8A will be in its new role without its complete suite of weapons and sensors."
Watch: P-8A will 'end 10-year gap' in RAF capability.
Nine P-8A Poseidons are expected to operate from RAF Lossiemouth, with the MOD having spent £3 billion on the fleet.
All nine aircraft are expected to be in the UK by the end of 2021.
Boeing P-8A Poseidon
- Height: 42ft 1¼in/13m
- Length: 130ft/40m
- Wingspan: 123ft/37m
- Speed: 490kt/907kmh
- Range: 4,500 miles/7,242km
- Ceiling: 41,000ft
Cover Image: An RAF P-8A Poseidon in the skies over NAS Jacksonville in the US (Picture: MOD).