Mike Walsh (Letters, November 22) asked me to explain the source of my figures on trams quoted in an article on November 17.

The source is Transport for London's Croydon Tramlink Impact Study and the figures quoted in the article actually made trams look even better than they are in reality.

In fact the study found that only 16 per cent of drivers had given up their cars to use the tram but 69 per cent had given up the bus and 7 per cent the train.

Getting people to swap one means of sustainable transport for another just undermines the financial viability of both. This is probably why the Croydon tramlink could no longer meet its operating costs in March.

Mike also mentions the Nottingham scheme which, at just under 18km long, is costing a staggering £14m per kilometer to build and wiped £10m off the profits of Carillion, the company building it.

Similar problems with the cost of development are also evident in tram schemes in West Yorkshire, South Hampshire and the extension of the Sheffield scheme.

I have nothing against trams but we have to be realistic. They are phenomenally expensive to build, not cheap to operate and even the most successful carry a fraction of the number of passengers that buses can.

Let's get the sustainable transport system we have in place already (buses) working at 100 per cent efficiency before we start thinking about expensive alternatives.

-Tony Mernagh, Brighton and Hove Economic Partnership, Pavilion Buildings, Brighton