The chief executive of English Nature has no hesitation in naming his favourite building as the Spirit of America, San Francisco by William L Pereira Associates,1972 (below).
'That wonderful arrow pointing to the sky. It's aspirational. It may not be perfect in design, but it combines the artistic with the functional.'
David Arnold-Forster is insistent that buildings harmonise with the environment, and that natural materials are used adventurously.
Slimbridge's new observation tower excites him.So does the Barn Elms Wetlands Centre south of Hammersmith Bridge: 'A natural landscape in the heart of London.'
He also enthuses about the new National Botanic Gardens in Wales.
He admires Foster's futuristic glass dome, elliptical in shape, which houses exotic plants. The 227ha Middleton estate is the setting for the first new botanical gardens to open for many years. Ivor Stokes, its director of botany, says: 'You can get round the world in an hour.'
Arnold-Foster adds: 'It blends with the landscape with its rolling shape, but it doesn't try to disguise itself.'
Are there buildings he does not like? 'I worked in the City but never got to like the Lloyd's building. It is incongruous in that setting. It is industrial and functional but not appealing.' But he prefers to discuss what he does like. 'I quite admire the new Parliament building. It seems to blend with the old and the new and is in keeping with its surroundings. I think its use of materials is excellent - and it's built to last.'