From Bill Gates’ solar toilets to the 'world’s greenest computer', we run down the top stories from the past seven days
High-speed line based on the kind of 'unrealistic assumptions' that led to taxpayers funding HS1 to the tune of £4.9bn
Prime minister slammed for "weak" reply to question over whether it will honour a manifesto commitment ruling out a third runway
Coalition of opposition groups raises funds for two judicial reviews over high-speed rail project
The government's green light for the High Speed 2 rail offers hope to the wider green economy
225mph trains linking London and Birmingham in 49 minutes to run by 2026 with lines to Manchester and Leeds promised by 2032
Who said what in the world of green business this week?
Government urged to press ahead with £32bn HS2 scheme in letters to three newspapers signed by executives, academics, and trade unions
Transport minister Justine Greening says no announcement on £34bn high-speed rail project will be made until January
Clean electricity, eco-driving and better scheduling could offset emissions from high-speed rail, report suggests