The company's data shows that employees on Tusker's Salary Sacrifice4Cars scheme typically select cars with average emissions of 30-40g/km less than their previous vehicle, driving down emissions across the company.

As an example, Tusker points to North Yorkshire County Council, which has a Green Car Scheme covering 30,000 staff. The average emissions of 200 new cars added to the NYCC fleet have now fallen to just 112g/km from an average of 156g/km of council employees' previous vehicles. When it comes to parting with their own money, employees select cars that are far less polluting, with better fuel consumption, smaller engines and lower carbon emissions.

The latest figures follow on from a survey Tusker conducted earlier this year which showed salary sacrifice drivers had selected cars with an average CO2 of 119.6g/km, compared to those on Tusker's contract hire fleet who had chosen vehicles with an average 149.5g/km.

The Tusker research also showed that cars on its salary sacrifice fleet had an average engine size of 1.4 litres and an average fuel consumption of 60.6mpg, compared to cars with average 1.9 litre engines and an average fuel consumption of 50.5mpg on the contract hire fleet.

Tusker managing director David Hosking said: 'What we are now seeing is a definite trend amongst employees on a salary sacrifice car scheme to select greener, cleaner, less polluting cars. As the example at North Yorkshire CC clearly shows this also has the effect of driving down emissions across the organisation.'

'In certain circumstances, where employees are doing high business mileages for example, there may still be a need for larger-engined, more comfortable, less carbon efficient cars and these will continue to be supplied through traditional company car schemes.

'But we are also finding that salary sacrifice cars are being used for business use as well as for personal use, so there is undoubtedly some cross-over between traditional business cars and salary sacrifice cars,' he added.