Ukrainian forces have destroyed dozens of Russian warplanes parked at airfields thousands of miles from the front lines, according to a source in the country’s security services, in one of Kyiv’s most audacious and sophisticated counter assaults since the beginning of the war.

Ukraine said its “Operation Spiderweb” attacked Russian warplanes worth hundreds of millions of dollars, utilizing drones that each cost under $1,000 and were launched from wooden containers carried on trucks.

Russia will take years to replace nuclear-capable bomber planes that were hit in Ukrainian drone strikes last weekend, according to Western military aviation experts, straining a modernisation programme that is already delayed.