Ukraine says it is prepared to use British long-range missiles – if they were supplied by the UK – to hit Russian forces inside Crimea.
It comes after Prime Minister Rishi Sunak said the UK would step up arms shipments to Kyiv – including discussions on sending Harpoon anti-ship missiles and Storm Shadow cruise missiles.
During President Zelensky's visit to the UK last week, he asked for fighter jets, as well as long-range missiles, to defend against the Russian invasion.
Ukraine has been attacking Russian targets on Ukrainian soil using US-provided the High Mobility Artillery Rocket System (Himars) missiles.
Himars only have a range of 50 miles which has allowed Russian forces to pull back their headquarters, barracks, and ammunition depots out of range.
According to defence analyst Dr James Bosbotinis, Storm Shadow would provide the Ukrainian Forces with the ability to hit Russian targets that are further away.
Storm Shadow is the RAF's long-range cruise missile. It's a 'fire and forget' missile that is programmed before the mission and, with a maximum speed of 621mph, can hit targets 350 miles away.
Each missile costs £2.2m.
Dr Bosbotinis said Storm Shadow would be "ideal" for targeting Russian facilities where fuel and munition are stored before being sent to frontline units.
According to the defence expert, the missiles would also be "ideal" for targeting Russian air and naval bases in Crimea.
The RAF and the French Air Force have used Storm Shadow missiles against ISIS and the UK also used them against Syrian forces in 2018, after the alleged use of chemical weapons.
However, there has been a reluctance from Whitehall to provide Ukraine with long-range missiles due to concerns that they may be used against targets in Russia, escalating the war.
Harpoon missiles are already in operation in Ukraine, donated by Denmark in May 2022, and were used in the attack on Snake Island.
At around £1m a missile, Harpoons are cheaper than Storm Shadow, they have a shorter range of 150 miles and can be launched from aircraft, ships, and even submarines.
Russia has been using Iskander-M tactical ballistic missiles to attack Ukraine on a large scale and is looking to Iran and North Korea to acquire more missiles.
According to Mr Bosbotinis, supplying Ukraine with long-range weapons would be simply levelling the playing field.
"We would be providing Ukraine with capabilities that Russia is employing, which Ukraine does not have access to," Mr Bosbotinis added.
Both Harpoons and Storm Shadow are subsonic missiles which means that they travel below the speed of sound.
Harpoons are predominantly designed to destroy enemy ships but are also capable of striking targets on land.
According to the defence analyst, Storm Shadow has a significantly greater range than Harpoons and is designed to hit "high-value hardened targets" that "the adversary does not want to have attacked", such as bunkers and hardened aircraft shelters.
The UK is the second largest military donor to Ukraine, after the US, having committed £2.3bn in 2022 and pledging to match that in 2023.