Exercise Trident Juncture, which began on 4 October, has seen armed forces from across the world come together to test the NATO Response Force (NRF) and other allied forces. All three UK Services – the Royal Navy, British Army and Royal Air Force – are involved.

More than 30 nations are involved in the five-week exercise, which is taking place in Italy, Portugal and Spain.

The UK and other participating NATO allies will commit 230 military units, 140 aircraft and more than 60 ships over the course of the exercise, drawing in a total of around 36,000 international troops.

Trident Juncture will put the NRF through its paces – with specific focus on how it responds to a crisis situation – demonstrating NATO’s readiness, flexibility and capability of responding to threats from any direction.

The two-part exercise, NATO’s biggest since 2002, will also ensure that NATO allies and partners can work together effectively.

Another important facet of Trident Juncture is to test the functions of the Very High Readiness Joint Task Force – or Spearhead Force – ahead of it becoming fully operational next year.

The UK is committing around 2800 personnel to Trident Juncture, including an Army Brigade Headquarters and Battlegroup, three Royal Navy warships and aircraft including Typhoon fighter jets and helicopters.

Amphibious ship HMS Bulwark will take part in the exercise together with helicopter carrier HMS Ocean, which is the UK’s largest warship and the flagship for Trident Juncture.