Croydon's tram system has been nominated for a Civic Trust design award for its environmentally friendly qualities.

Westminster tube station, Doncaster's futuristic Earth Centre building and Jubilee Campus at Nottingham University are also in the running for the award, which will be announced in April.

Nominees had to show sustainable design' principles, such as using recycled materials. The impact on the local environment was also considered.

Croydon's tram system has already won three awards and Theo Spring, for system operators Tramtrack Croydon, said: "The system now carries 18 and a half million passengers a year without having a negative impact on air quality."