MORE petrol-powered versions of the Passat saloon and estate and the Tiguan SUV are being introduced by Volkswagen as diesel car sales in Britain continue to fall.

Both VW ranges are being expanded with some 50 new models joining the line ups which so far have been predominantly diesel.

The number of diesel cars being registered in the UK this year has slumped by almost 10 per cent while the popularity of petrol models has increased by more than five per cent.

The shift follows changes to the vehicle tax system introduced in April and growing concerns about the environmental impact of diesel cars.

VW is now offering with Passat with 1.4, 1.8 and 2.0-litre turbo petrol engines and is expanding the Tiguan range with seven new petrol models.

Prices for the new Passat saloons run from £21,610 for a 1.4-litre saloon in S trim to £32,655 for a high specification 2.0-litre, 220ps R-Line model while the new Tiguans cost from £25,000 to £32,215.

The new Passat estates are priced from £23,210.

For company car drivers a Passat 1.4 TSI ACT 150 PS SE Business six-speed manual, with an on-the-road price of £23,775 and officially rated at 56.9mpg with emissions of 115g/km, has a BIK tax rating of 22 per cent meaning a 40 per cent tax payer would incur a tax charge of £6,880 over a typical three years behind the wheel.

An equivalent Passat 2.0 TDI 150 PS SE Business six-speed manual driver would face a tax bill of £7,746 over the same period thanks to the car's £25,675 price and its 23per cent BIK rate.

Volkswagen says the new petrol-powered Passats - which have the same equipment specifications of their diesel siblings on a like-for-like trim basis - will cost around £1,900 below their diesel equivalents, making them a compelling alternative.

In the Tiguan range a 1.4-litre 125ps TSI 2WD derivative has been introduced on the SE and SE Nav trim lines while the 1.4-litre 150ps 2WD DSG configuration is now available in SEL and R-Line models which, priced from £29,900 for the SEL trim, is £500 cheaper than an equivalent specification diesel version.

The 150ps 1.4 engine is also being fitted to four-wheel-drive Tiguans for the first time which are rated at 155g/km (42.2mpg) for manual versions and 163g/km (40.2mpg) for DSG automatics.