Sadiq Khan has demanded Volkswagen cough up £2.5m ($3.1m) in underpaid congestion charges as a result of the 'dieselgate' scandal. The Mayor of London wants the German car maker to pay the sum to Transport for London after his office found 80,000 of its vehicles had escaped the fee as a result of fake emissions data.

VW accepted a colossal fine of $15bn (£12.4bn) in June after it installed devices that reduced vehicle emissions during tests. Khan's office says almost one sixth of the 500,000 VW cars registered to London addresses avoided paying the charge for years.

The mayor now wants to recoup that money he believes is owed to TfL and has written to the managing director of the company to demand payment.

"VW vehicles qualified for the congestion charge greener vehicle discount on the basis that they emitted less than 100g of CO2 per km and met the Euro 5 standard… owners of affected VW vehicles [inadvertently] claimed a discount to which they were not entitled," he wrote.

The carmaker however appears reluctant to stump up the cash.

"Volkswagen products perform well in independent real world emissions testing against new cars in general," a statement said. "It is therefore difficult to understand why our products might be singled out for pollution penalties."

The embattled brand will will shed up to 30,000 jobs globally as it prepares to pay €3.7bn (£3.2bn, $3.92bn) a year to settle the fine . It will soften the blow by recruiting 9,000 new workers as it modernises its approach to carmaking and focuses more on hybrid vehicles.

Chief executive, Matthias Müller said of the change: "The VW brand needs a real shake-up and that is exactly what the future pact has turned out to be."