He said the Type 45 destroyer would leave “in the next few days, as soon as it’s got ammunition on board” but did not say how long it would take to arrive in the Mediterranean.
The ship had been undergoing maintenance on the south coast. France and Greece have already deployed assets towards Cyprus.
Sir Richard said the drone targeting the RAF base was assessed to have launched from Lebanon by an Iranian-aligned group.
He disagreed with claims the UK’s action had started too late and said his priority was to protect British people and interests, echoing the words of Prime Minister Sir Keir Starmer earlier in the week.
Sir Richard said it became clear early on “that Iran’s response was going to be much broader, wild and indiscriminate, and rather reckless compared to what we saw in the 12-day war last summer”.
He added that in the days since the latest conflict started, the UK assessed its options to increase its presence and ability to defend allies and its own interests.
Leader of the Opposition Kemi Badenoch accused Sir Keir of “sitting on the fence” over the UK’s response to the Middle East conflict.
Speaking on Saturday at the Conservative Party’s Spring Conference in Harrogate, North Yorkshire, Badenoch said that “at a time when Britain needs strong and decisive leadership, we have a prime minister who is too afraid of making the wrong decision, too afraid to make any decision at all”.
“We are in this war, whether Keir Starmer likes it or not,” she added.
Badenoch said Britain has been described as “weak” and that our allies have “accused the UK of deserting them, going missing in action”.
While the UK was “dithering”, the US, Greece and France have all sent ships to Cyprus, she said.
“Ours is stuck in Portsmouth Harbour, and may set sail some time this week,” Badenoch added in reference to HMS Dragon.