Two men are said to have been employed by the Kremlin to record and tap into conversations of world leaders at the World Economic Forum in Davos, Switzerland.

Police allegedly took two Russians in for questioning in August 2019 after they aroused suspicion.

They claimed they were on a three-week holiday and told Swiss officers their diplomat passports gave them immunity from any charges.

However, Tages-Anzeiger claims neither of them were registered as a diplomat.

They were released and left the country after police did not have enough evidence to hold them, according to reports

.A spokesman for the Russian embassy in Bern dismissed the claims, saying two Russian diplomats accredited outside Switzerland had been checked and allowed to go on their way.

He said: ‘Diplomatic passports are given to high-ranking officials, not to manual labourers.

‘I think this was probably a dumb joke.’

Maria Zakharova, a spokeswoman for the Russian Foreign Ministry in Moscow, said she was not aware of the incident.

A police spokeswoman said: ‘It is true that we checked two Russian citizens in Davos and they identified themselves with diplomatic passports, but we could not ascertain any reason to detain them.

‘They were allowed to go.’

Investment fund manager Bill Browder – who blames Russian officials for the death of his lawyer, Sergei Magnitsky who died in a Moscow prison in 2009 after complaining of mistreatment – has claimed the alleged incident shows the reach of the Russian state.

He said: ‘The Russians are actively targeting all of their enemies in all different countries – they have huge resources and Davos is an important place, and this is the one place I can come and personally challenge Russian officials over the murder of Sergei Magnitsky.

Russian prosecutors have said they suspect Browder of ordering a string of murders, including of Magnitsky.

The financier has dismissed these claims as ‘ludicrous’.