The attempted coup exposes the political instability in Russia, say sources (Picture: Reuters/Rex)

Britain should ‘prepare for the fall of Vladimir Putin’ following a failed attempt to oust him, senior government sources have said.

An apparent coup was narrowly avoided when Wagner leader Yevgeny Prigozhin stopped his mercenary group’s planned march from Rostov to Moscow this weekend.

Putin had spoken on television vowing ‘brutal’ retaliation against rebels if they continued with the revolt.

But Prigozhin escaped punishment as part of an agreement that will see him exiled in Belarus.

The US secretary of state, Antony Blinken, said the failed coup showed ‘real cracks’ in Putin’s regime. ‘This was a direct challenge to Putin’s authority,’ he told CBS News. ‘It raises profound questions.’

US intelligence agencies learnt of Wagner’s plans days before Prigozhin ordered his troops to seize control of cities Voronezh and Rostov-on-Don, according to The Washington Post.

But they decided not to publish the intelligence, as they had done in the weeks prior to the invasion of Ukraine. Instead they let events in Russia play out.

Yevgeny Prigozhin is the exiled leader of the Wagner mercenary group (Picture: Reuters)

Wagner fighters pull out of the headquarters of the Southern Military District to return to base, in the city of Rostov-on-Don, Russia (Picture: Reuters)

British officials have predicted political unrest in Russia since the beginning of the war, but were surprised at how quickly events unfolded over the weekend. Diplomats were forced to rapidly prepare for various possibilities.

‘From the very beginning of the invasion, one of the most obvious scenarios was that the war could lead to political unrest back home in Russia,’ a senior UK Government source told The Times.

‘We have to wait, watch and see what comes next. This could be chapter one of something new. Or it might be all over for Wagner. We must prepare for a whole range of different scenarios.’

Meanwhile, John Glen, the chief secretary to the Treasury, said Britain continues to support Ukraine but would not get involved in what was happening in Russia.

Putin addressed the nation on Saturday warning rebels there will be ‘brutal’ retaliation if they continued with the revolt (Picture: AP)

Prigozhin leaves the headquarters of the Southern Military District amid the group’s pullout from the city of Rostov-on-Don, Russia this weekend (Picture: Reuters)

John Foreman, the former British defence attaché in Moscow, said Prigozhin ousting Putin was not something people should wish for.

‘Prigozhin is not some sort of liberal, peace-loving democrat. He’s a fascist,’ he added.

Lithuanian president, Gitanas Nauseda, who will host a Nato summit next month, said Europe’s eastern borders would need to be strengthened if Prigozhin and some of the Wagner group end up in Belarus ‘with unclear plans and unclear intensions’.

Lord Richards of Herstmonceux, a former UK chief of the defence staff, said Putin remained powerful and warned the west about underestimating Russia.

He told Times Radio that Ukraine’s struggling counter-offensive showed the ongoing strength of the Russian army.

He added: ‘Despite the weakened state, arguably of Putin, we’re in for a long haul here. And that actually is the worst of all worlds for the west.’

Get in touch with our news team by emailing us at [email protected].

For more stories like this, check our news page.

‘This could be chapter one of something new,’ a senior UK Government source said.