The letter, to UN Security Council President, comes after Iran’s attack on the tanker Mercer Street which resulted in two deaths, including that of a Briton.
Tehran has denied any involvement in Thursday's attack on the Mercer Street - a Liberian-flagged, Japanese-owned petroleum product tanker managed by Israeli-owned Zodiac Maritime.
It comes after Britain’s top soldier warned Iran it had made a “big mistake” after the drone attack on the tanker.
General Sir Nick Carter, the Chief of the Defence Staff, stressed the West would have to “restore deterrence” to avoid such incidents spiralling into more dangerous situations which could be “very disastrous”.
Speaking on BBC Radio 4’s Today programme, Sir Nick said: “What we need to be doing, fundamentally, is calling out Iran for its very reckless behaviour. They made a big mistake on the attack they did against the Mercer Street.
“Ultimately, we have got to restore deterrence because it is behaviour like that which leads to escalation, and that could very easily lead to miscalculation and that would be very disastrous for all the peoples of the Gulf and the international community.”
He said the UK will work with allies to decide the best way of providing protection to shipping in the region, but a return to a system of convoys escorted by warships “may not necessarily be the right method”.
He did not specify any retaliatory action which could be more sanctions on Iran, a military response or diplomatic steps.
Meanwhile, Britain’s maritime trade agency said boarders have left a tanker that was reportedly seized off the coast of the United Arab Emirates and the vessel is safe.
Maritime security sources said the asphalt tanker Asphalt Princess had been seized by suspected Iranian-backed forces, which Tehran denied.
The United Kingdom Maritime Trade Operations said what it described as a potential hijack incident was now “complete” but gave no details in a warning notice based on a third-party source. It did not name the vessel involved.
Regional tensions have worsened since 2018, when Washington re-imposed sanctions on Iran after then US president Donald Trump abandoned a 2015 nuclear deal between Tehran and global powers.