Watch - Royal Navy: Portsmouth based HMS Dasher rescues Swedish submariners with "emergency" caffeine boost

The light-hearted moment came during a NATO exercise with HMS Dasher rushing to the aid of allies in need of a coffee boost in the Baltic. It is believed to be the first ever re-supply by the class of fast boat and a submarine in their near-40-year careers.

The transfer of supplies was no mean feat, with Dasher having to remain at least five metres away due to the submarine pumping out pressurised gas. A heaving line then had to be thrown to the submarine with the coffee, and some Italian biscuits for good measure, put into a waterproof bag to be passed over.

Get The News for less than a fiver with our new value subscription package

Lieutenant Jack Mason, HMS Dasher’s Commanding Officer, said: “Although on this occasion it was only ground coffee, we’ve demonstrated allied co-operation, the ability to communicate between a P2000 and a Swedish submarine via NATO, and the ability for a P2000 to deliver critical stores at short notice to assist with submarines maintaining their operational readiness.”

HMS Dasher is staking part in Baltops, an annual exercise which has been running since the early 1970s. Around 50 ships, submarines and support vessels, more than two-dozen aircraft, and around 9,000 personnel from 17 nations, are taking part covering 40,000 square miles from Jutland and the Greta Belt in the West to the Bay of Gdansk.

Click here to visit our newsletter page and sign up for free emails - featuring the city’s best headlines, Pompey updates and much more

There are currently six P2000 patrol boats from the Coastal Forces Squadron taking part in Baltops, HMS Archer, Biter, Dasher, Example, Pursuer and Smiter. Two of which are conducting extensive work with the Royal Navy’s Mine Threat and Exploitation Group, who are using the craft as launchpads for the latest robot tech monitoring the underwater battlespace through uncrewed underwater vehicles (UUVs).

The other four boats are working with US Navy surface and aerial drones, frequently attacking the participants to test their responses dealing with small, fast and agile craft intent on harming much more powerful warships.

The replenishment at sea exercise took place during a break from these exercises.