Britain said Saturday it had barred a Russian delegation from attending the Farnborough air show because of the Ukraine crisis, sparking an angry reaction from Russia.

The Russian embassy in London expressed "regret" that Britain had not issued visas to a large part of its delegation and demanded an urgent explanation.

The Farnborough International Airshow (FIA) is a key event in the aviation sector calendar, with Russia usually sending a sizeable contingent as it seeks foreign sales.

Britain has been a strong backer of EU asset bans and travel freezes against Moscow over what it says is Russian interference in conflict-torn eastern Ukraine.

Britain's Foreign Office said it invites representatives from foreign governments to attend Farnborough as government guests, even though it is a commercial event.

"But due to Russian actions in Ukraine, no representatives from the Russian government have been issued HMG (Her Majesty's Government) invitations to FIA 2014," a spokesman said in a statement to AFP.

London had also taken "clear action" to remove Russia from the list of countries eligible to buy British planes or equipment "in order to discourage Russian attendance" at Farnborough, it said.

The Russian embassy said in a statement that it "expresses its regret that the visit of a greater part of the Russian delegation... is falling through".

Delegates from the Russian industry and trade ministry, the Russian space agency and air transport agency, plus dozens of Russian companies had been affected, along with technicians for Russian aircraft meant to be flying at the show, it said, without giving specific numbers.

"The Embassy of the Russian Federation has asked for relevant explanations in an urgent note to the Foreign and Commonwealth Office," it said.

Russian delegates at other events including a security forum and the London book fair had also been denied visas earlier this year, it added.

Talks between Russian weapons exporter Rosoboronexport and foreign partners on Monday had been "practically ruined" because of the visa denials, a source in the Russian delegation told RIA-Novosti news agency.

Russia will also cancel several presentations, for example, of its military helicopters, according to the source.

In March, London suspended all bilateral military cooperation and halted arms exports to Russia, while warning that the West and Russia faced changed relations for decades.

In 2012, Russia complained of delays in obtaining visas for the last Farnborough Air Show, although at the time Britain said that was due to people applying too late.