In the last 18 months Peter Head has visited 23 countries discussing a transition from the industrial model of city development to an ecological one based on efficient use of renewable resources, including energy. He will present both retrofit and new development scenarios which are emerging, and his analysis, based on evidence of real examples of best practice, makes an economic case for rethinking forms of cities to enable human development to flourish. Peter Head is a Senior Director at Arup, one of the world's most successful engineering and planning consultancy companies, with over 10,000 staff in 37 countries. Peter is a civil and structural engineer who has become a recognized world leader in major bridges (he received an OBE for successfully delivering the Second Severn Crossing as Government Agent), advanced composite technology and now in sustainable development in cities. He has won many awards for his work including the Award of Merit of IABSE, the Royal Academy of Engineering’s Silver Medal and the Prince Philip Award for Polymers in the Service of Mankind. He was appointed in 2002 by the Mayor of London as an independent Commissioner on the London Sustainable Development Commission and leads the planning and development sub-group of the Commission. He joined Arup in 2004 to create the Planning and Integrated Urbanism team, which he directs from London. This lecture is a summary of the prestigious Brunel lecture for the UK Institution of Civil Engineers.