The yacht caught with 200kg of cocaine on Tuesday was almost certainly heading to Bermuda, according to the captain of the HMS Argyll, which seized the vessel.

The Royal Navy ship was returning to the Caribbean after providing hurricane relief to Bermuda in the wake of Hurricane Gonzalo.

They seized the yacht off the coast of Bermuda and found that it was carrying drugs with an estimated street value of $15 million.

Captain Paul Hammond told The Royal Gazette: “We had no information on where the yacht was going.

“It wasn’t that seaworthy and they had no navigation plan, so we can’t say for certain it was going to Bermuda, but when we found it, it was about 100 miles southwest of Bermuda heading towards the Island.

“Arguably, there is nowhere else it could be going if it wasn’t going via Bermuda, so we strongly suspect that it was heading to Bermuda.

“Whether it was going to move on from there afterwards, I don’t know.

“Whether the drugs were destined to land in Bermuda, we will never know, I guess.”

Capt Hammond could not reveal the nationality of the suspects but could confirm that they were not British.

He added: “That was another suspicious point: that they weren’t British and appeared to be heading towards Bermuda was another one of those trip wires, as we call it, when you think, ‘This doesn’t seem to make sense’.”

The two suspects and the contraband were handed over to the US Coast Guard, who delivered them into the custody of the American authorities. HMS Argyll used an element of surprise to stop the yacht in its tracks. “We overwhelmed them with force,” Capt Hammond said of the raid.

“We found the yacht using the helicopter, which they hadn’t spotted.

“Then what we do is standard procedure: we try to stay behind the yacht so they don’t see us coming, then we have a way of approaching with the ship via fastboat and helicopter so we all arrive at the yacht at the same time and overwhelm them with a show of force — a military presence.

“They don’t have much they can do about it at that point; they just look at us in disbelief. They probably didn’t spot us until we were about a mile away. In that short space of time, there is nothing they could have done to hide what they were doing.”

Asked about their reaction when they were approached, Capt Hammond said: “They didn’t really say anything. We were given approval to get on board and we could tell from the outset that they appeared suspicious. Usually when you come across a yacht in the middle of the Atlantic, they wave at us and are pleased to see us, but these guys clearly weren’t.

“They didn’t really engage us in conversation and then we got approval to go on board and have a look at the yacht. That’s when we found the drugs.”

UK Defence Secretary Michael Fallon said in a release: “This is yet another clear demonstration of the flexibility and versatility of the Royal Navy. HMS Argyll and her crew are playing a key role in disrupting the drugs trade which blights the UK. The British people should be proud of the work that they undertake on our behalf.”

This is HMS Argyll’s second bust in two months having seized £25 million (about $40 million) in cocaine in August. She is due to continue counter-narcotics operations in the Caribbean for a few more weeks.