Ukrainian forces wiped out a £17.7 million Russian spy plane to tee up an attack on one of Vladimir Putin’s submarines, the country’s intelligence service has claimed. The Security Service of Ukraine (SBU) said the audacious strike saw Russia’s only Il-38N aircraft based in the Black Sea destroyed, setting the groundwork for the attack on the Varshavyanka-class submarine.

It said the aircraft, designed for naval reconnaissance and monitoring waters, was capable of detecting the newly-developed ‘Sub Sea Baby’ underwater drone used to hit the boat in the port of Novorossiysk, southern Russia. In a post on Telegram, the SBU said: “The disabling of this anti-submarine aircraft ensured the successful execution of the main part of the special operation – the explosion of the “Varshavyanka” class submarine.” An aerial drone, carrying an airburst warhead with “2,000 striking elements”, was used to disable the plane at the Yeisk airbase, the SBU said.

The drone struck above the aircraft’s main radars and equipment and also damaged the engine, the agency claimed.

Footage released by the SBU purportedly showed a UAV honing in on the ‘Sea Dragon’ plane next to a runway.

“The released footage of the successful attack on the Russian aircraft clearly demonstrates the real level of protection of enemy strategic facilities, which is significantly different from internal reports and public statements of the Russian Ministry of Defense,” the SBU said on social media.

The agency announced Ukrainian forces had attacked the diesel-electric submarine last week, with reports suggesting 14 Russian sailors were killed.

It said the hit Il-38N “actively opposed” SBU drones and could have prevented the submarine from being struck.

Ukraine claimed the aircraft was Russia’s sole Il-38N in the Black Sea region.

The plane is an upgraded version of the Cold War-era Il-38, often known by its NATO reporting name of May.

It is not clear how many Il-38Ns Russia has at its disposal, although reports from 2017 suggest Russia planned to have 30 of the updated planes which can also carry out anti-submarine operations and fire torpedoes.

Moscow has yet to comment on the attack claims.

Ukraine has regularly used drones to strike Russian naval assets in the Black Sea during the bloody war which is approaching its fifth year.

On Wednesday, Ukrainian President Volodymyr Zelensky said he would be willing to withdraw troops from the country’s eastern industrial heartland as part of a plan to end Russia’s war, if Moscow also pulls back and the area becomes a demilitarised zone monitored by international forces.