Scanning the faces of waiting crowds at Portsmouth harbour, a line of young sailors could barely contain their excitement at being reunited with loved ones after months at sea.

They waved frantically as family members came into view. There were tears of joy, grins of anticipation and hugs of relief as HMS Diamond finally pulled up alongside.

The Type 45 destroyer arrived home at the weekend following a landmark mission to defend international shipping in the Red Sea from strikes by Iran-backed Houthi fighters in Yemen.

In that time, it made Royal Navy history by blasting seven Houthi drones out of the sky during a single swarm attack – the highest number of enemy aircraft to be taken out in one day by any British warship.

The vessel scored another first when it shot down a ballistic missile in April that was targeting a merchant ship – the first time any part of the UK armed forces has eliminated such a weapon in combat.

HMS Diamond had been in line for yet one more first – becoming the first port of call for John Healey, the new Labour defence secretary, within hours of him taking charge on Friday.

But an issue with the helicopter he had been travelling on meant that the aircraft had to turn around on Friday evening instead of landing on the warship as it was sailing off the coast of Plymouth.

By contrast, Sky News did make it on board – travelling by sea instead of air to meet up with the giant vessel.

We spent 24 hours with its crew of some 225 sailors who have been at sea for 151 days. During that time they have sailed around 44,000 miles, including in the Red Sea and the Gulf of Aden as part of a US-led coalition to protect merchant ships transiting the area.

The captain, Commander Peter Evans, showed us the air defence system that was used to destroy most of the drones and to take out the ballistic missile. The ship brought down a total of nine Houthi drones during its deployment.

“The weapon we are all talking about at the moment is the Sea Viper system, which are in those square doors in front of us,” he said, gesturing to the white-coloured squares that formed two large rectangular slaps on an elevated platform at the front of the ship.

“The door opens and the missiles are about 4 or 5 metres long. By the time it has cleared the bridge roof it is already way, way over the speed of sound,” said the commanding officer.

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Asked what message the destruction of a Houthi missile sent, he said: “We can be reactive, we can be fast, we can be flexible and we are certainly capable of protecting ships at sea.”

In the operations room, a windowless area inside the ship, filled with lines of screens and monitors displaying radar and satellite images as well as video feeds and other data, a junior sailor recalled the moment HMS Diamond went up against the ballistic missile.

“We heard the general alarm and you don’t think it is real when it is happening,” said Leading Hand Erin Graham, 22, from Middlesborough.

“But then when it actually pops up on radar, we know we have got seconds [to react].”

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The sailor, who heads a team that does electronic warfare, said the training kicked in.

“You knew that you couldn’t put a finger wrong but it was a very smooth engagement from start to finish and the ship performed excellently.”

Asked how she felt about coming home, she said: “I honestly can’t want.”

She was to be met by her mother, father, their respective partners, her twin sister, her younger sister and her grandmother.

As for what she was looking forward to doing, the young sailor listed waking up in her own bed, driving and seeing her dog. “Normal home stuff.”