Police and paramedics today swooped on London's Mayfair where a Russian oligarch's chauffeur died from a cardiac arrest.

A large cordon was established on Albemarle Street and Dover Street after the man collapsed in the road.

Passersby were seen carrying out CPR on the man who had chauffeured a 'high profile Russian couple' to Oswald's Club, it is believed.

A witness said: 'He drove them outside, they got out and then he also got out and collapsed.'

Police and paramedics were still at the scene this evening after the 'high profile Russian couple' chauffeur collapsed and died in the street

A large cordon was established on Albemarle Street and Dover Street after the man collapsed in the road

Police were called to the scene in London's wealthy Mayfair district this afternoon after a man collapsed in the street. Officers are pictured at the scene

Officers were pictured erecting a protective tent over what is believed to be the body of a man who died from a suspected cardiac arrest this afternoon

Police were pictured erecting a protective tent over what is believed to be the man's body

A cordon was established on Albemarle Street and Dover Street after the man collapsed in the road

The man was treated near a Mercedes limousine with black out rear windows in Albermarle Street, near the junction with Grafton Street.

The black Mercedes did not have diplomatic plates and was parked outside top jewellers Garrard and opposite Asprey.

A Met Police spokesman said: 'At approximately 15:15hrs on Thursday, 21 June, police responded to a call from the London Ambulance Service (LAS) relating to a man taken ill on Albemarle Street in Mayfair.

'Officers attended the scene. At the location they found a man being treated by the LAS.

'He was subsequently pronounced dead at the scene.

What is it like inside Oswald's Club, a haunt for the rich and famous? The club offers its members a focus around wine as well as a cellar where they can store it Based at 5 Hertford Street, Oswald's Club is an exclusive haunt for London's elite. It is owned by business mogul Robin Birley, whose portfolio also includes 5 Hertford Street. Oswald's Club, which is named after Birley's grandfather, offers members a focus around wine. Oswald's Club consists of an 80 cover restaurant and storage space for members' private collections Members can cellar their own wines or purchase them from the wine shop and drink them at a minimal mark-up in the ground-floor restaurant, first-floor bar or on the little terrace at the back, according to How to Spend it. It consists of an 80 cover restaurant and storage space for members' private collections. The club, which opened earlier this year, is the former site of another famous London club, The Albemarle. It was notorious for being the location of the incident that led to the first libel action trial of Oscar Wilde, who was a member. Advertisement

A large cordon has been established on Albemarle Street and Dover Street, which is home to Victoria Beckham’s store

The scene today on Albemarie Street in Mayfair where London Ambulance Service has confirmed a man has died from a suspected cardiac arrest

The Metropolitan Police said there were concerns the man could have been exposed to poison but there was no forensic evidence to suggest that

'Due to concerns the victim may have been exposed to a poison, specialist officers attended but found no evidence that would indicate the victim had been poisoned.

'There are no other reports of people being taken ill.

'Cordons were put in place around the area to allow the emergency services to carry out their work.'

Pictures showed emergency services vehicles at the scene this afternoon as well as the police helicopter.

The area is home to a number of foreign embassies and government buildings, including Cayman Islands government office, Saudi Arabia visa office, Government of Bermuda.