LONDON, March 31. /TASS/. United Kingdom Security Minister Ben Wallace called a search of Russian aircraft in London Heathrow Airport on March 30 a routine procedure.

"It is routine for Border Force to search aircraft to protect the UK from organized crime and from those who attempt to bring harmful substances like drugs or firearms into the country," according to Security Minister’s official statement.

"Once these checks were carried out the plane was allowed to carry on with its onward journey," the added.

It was reported earlier that an aircraft of the Russian airline Aeroflot underwent a surprise search by the British boarder guards at Heathrow airport on March 30.

Aeroflot executives said on Friday the UK authorities had searched the jet, bound to perform a return flight SU2583 from London to Moscow, without providing any explanations for their actions. In violation of the effective international rules, the captain of the jet was locked in the cockpit. The airline said the search fully ran counter to the international practice for such operations.

Relations between Russia and the UK have been tense after on March 4, former Russian military intelligence (GRU) Colonel Sergei Skripal, who had been convicted in Russia of spying for Great Britain and exchanged for Russian intelligence officers, and his daughter Yulia suffered the effects of a nerve agent in the British city of Salisbury.

British Prime Minister Theresa May said the substance used in the attack had been a Novichok-class nerve agent developed in the Soviet Union. London expelled 23 Russian diplomats and announced other restrictive measures against Moscow.

Moscow rejected all of the United Kingdom’s accusations, saying that a program aimed at developing such a substance had existed neither in the Soviet Union nor in Russia. In retaliation to the UK’s steps, 23 British diplomats were expelled, the British consulate general in the city of St. Petersburg was closed and the British Council had to shut down its operations in Russia.