The Ministry of Defence is insisting the deployment of the two vessels - a Type 45 destroyer equipped with anti-aircraft missiles and an anti-submarine Type 23 frigate - is routine. However, the Royal Navy’s presence in the key strategic waterway is a clear sign of how seriously military chiefs are taking the situation.
An MoD spokesman told Express.co.uk: “The UK and our international allies are unwavering in our support for Ukraine’s sovereignty and territorial integrity.
“We are working closely with Ukraine to monitor the current situation and continue to call on Russia to de-escalate.”
“Our Armed Forces continue to support Ukraine through our training mission Operation Orbital, which has trained over 20,000 members of the Armed Forces of Ukraine, and the UK-led Maritime Training Initiative.”
The two ships will sail through the narrow Bosphorus strait which separates the European and Asian areas of Turkey next month, The Sunday Times reported.
In addition, RAF F-35B Lightning stealth jets and Merlin submarine-hunting helicopters stationed on the HMS Queen Elizabeth, also stand ready to be deployed to support them if necessary.
The MoD has also confirmed six RAF Typhoons were being sent to Romania to patrol the skies around the Black Sea.
Tensions between Moscow and Kyiv have been rising amid a build-up of Russian troops along the border and clashes in eastern Ukraine between the army and pro-Russian separatists.
Citing Ukrainian intelligence, the country’s defence minister Andrii Taran last week claimed Russia was massing 110,000 troops on Ukraine's border in 56 battalion-sized tactical groups close to the Donbass region to the east, and in Crimea, which Vladimir Putin annexed in 2014.
He also warned: "Crimea's infrastructure is being prepared for potentially storing nuclear weapons.
"The very presence of nuclear munitions in the peninsula may spark a whole array of complex political, legal and moral problems."
Speaking to CNN, also last week, Ukraine’s President Volodymyr Zelenskiy admitted he and his countrymen were prepared for invasion at any moment.
He said: "We know it, from 2014 we know it can be each day.
"They are ready, but we are also ready because we are on our land and our territory.”
Speaking to the BBC’s Andrew Marr yesterday, the Russian ambassador to the UK said he has not seen Foreign Secretary Dominic Raab for more than a year amid rising tensions.
His remarks came after Mr Raab said the UK and US were determined to stand together against what he described as Russia's "malign behaviour" following a major cyberattack on the West.