The Russian security services have previously claimed that Osmayev was 'a graduate of a prestigious institution of higher learning in Great Britain', and is from a prominent Chechen family opposed to Putin.

Shown on Russian state-run TV with his hands bandaged and wounds on his face, Osmayev has been on Russia's wanted list for a number of years.

He is believed to have lived 'for many years' in London, which, if true, will inflame Russian concerns that Britain is a safe haven for alleged Islamic extremist terrorist suspects from Chechnya.

The arrests of two suspects was made by the Ukrainian special services anti-terrorist unit Alfa after an accidental explosion early last month in an Odessa apaprtment which killed a third alleged terrorist, Ruslan Madayev.

The revelation comes in the final week of campaigning for Sunday's presidential election which Putin is virtually certain to win convincingly despite recent opposition street protests against his authoritarian rule.

Osmayev, believed to be 30, and fellow gang members were on a mission ordered by Chechnya's most wanted rebel leader Doku Umarov, it was claimed.

In January last year, Umarov targeted passengers emerging from British flights at a Moscow airport. A total of 37 died and 180 were injured.

His goal is an Islamic state based on Chechnya and run under Sharia law in the tinderbox Caucasus region.

The alleged plotters, all ethnic Chechens, came to Ukraine from the United Arab Emirates via Turkey with 'clear instructions from representatives of Doku Umarov', it was claimed.

On Osmayev's laptop was found hidden camera footage of Putin's motorcade in Moscow, and it is believed this was to be the target of the assassination bid.

Footage was shot 'so that we had an understanding of how he was protected', said Osmayev, who allegedly planned to use military mines to assassinate the premier.

'The end goal was to come to Moscow and to try to stage an assassination attempt against premier Putin,' he said. 'The deadline was after the election of the Russian president.'

Russia's Channel One television station said the suspect had revealed to investigators the site of a cache of explosives already in place near Kutuzovsky Prospekt, a major Moscow highway used daily by Putin in a heavily-armoured limousine to go to and from work.

An FSB official said the explosives would have created 'a serious blast, powerful enough to tear apart a truck'.

The British-educated man is co-operating with Ukrainian interrogators hoping that this will avoid his extradition to Russia.

Another suspect Ilya Pyanzin, who had a Kazakh passport, said: 'They told us that first you come to Odessa and learn how to make bombs.

'And then later, in Moscow, you will stage attacks against commercial objects, with the subsequent assassination attempt against Putin.'

The existence of the plot was confirmed by Putin's spokesman as well as the Ukrainian Security Service (SBU) and its Russian counterpart the Federal Security Service (FSB).

'I confirm this information but am not commenting now,' said Putin's spokesman Dmitry Peskov.

News of the arrests comes a day after thousands of protesters held hands to form a ten-mile human chain around Moscow city centre.