Iran's threat to British shipping in the Gulf "hasn't gone away", said head of the Royal Navy Admiral Tony Radakin.
Speaking to the BBC on Tuesday, he described the Iran Revolutionary Guards’ capture of the British-flagged tanker the Stena Impero in the Strait of Hormuz in July as "aggressive" and "outrageous".
He stressed that London was working on de-escalating tension with Iran following the incident.
At the same time, however, the navy would maintain a heightened military presence in the Gulf, he said.
Radakin also made clear that the UK would continue to work with a US-led coalition, known as "Operation Sentinel", to provide maritime security in the Gulf, rather than join a rival European operation being set up by France.
While he welcomed the French initiative, he said there were "very simple practical reasons" for the UK to remain part of the US-led operation, including existing strong military ties.
He added that the UK had "been very clear" it did not support the Trump administration's policy of maximum pressure on Iran, said the BBC.