Is this Britain’s lightest modern bus?

Photographed on test on a public road in rural Hampshire in March was the Bristol Superlight, an ultra low-weight zero-emission prototype single-decker developed by UK automotive engineering consultancy Frazer- Nash Research.

Frazer-Nash Research is owned by Indianborn Kamal Siddiqi’s Kamkorp Group, which acquired the Bristol Cars luxury sports car business in 2011, hence the use of a brand name and logo familiar to the bus community from the days of the erstwhile Bristol Commercial Vehicles. It also owns the Metrocab black taxi manufacturer.

With over 25 years’ experience of developing electric drive systems for vehicles, the company — which develops products from concept to low volume production — it says the driveline of the Superlight bus is scalable and will power anything from a small car to a heavy commercial vehicle or monorail.

The prototype was first registered in August 2015 and when demonstrating it last year in the Swiss ski resort of St Moritz, where Siddiq has a home, Frazer-Nash Research director of regional operations Gordon Dixon said that it will use between a quarter and a fifth of the fuel of a conventional bus.

He describes it as ‘zero-emission capable’, as it has a 100% electric drive, but uses a 1litre petrol engine to charge the lithium battery when it runs low. Engines could also run on benzene.

Dixon says the secret to achieving this is to make the vehicle exceptionally light.

The body is made from carbon fibre and Kevlar composite and the complete vehicle weighs 3,500kg unladen; gross weight of the dual-door 27-seater is 4,840kg. The BYD/ Alexander Dennis Enviro200EV electric buses operating for Go-Ahead London are 11,900kg unladen.

‘Why should we have a 12tonne bus that’s carrying half a tonne of passengers? That’s an old way of thinking,’ he says.

The Bristol Superlight on test on the public highway in Farnborough in March. It is normally kept within a secure compound away from public view.