David, David, David. What were you thinking? The rosy-cheeked opposition leader only popped into his local Tesco in west London for "some bits of salad" - and can't have been more than five minutes foraging among the rocket and radicchio - but on his return, where once rested Cameron's gleaming two-wheeler (an "old friend", he joked) stood a denuded bollard. Indeed, "bollards!" is what he might have muttered, as dozens of busy Londoners walked on by. Bewildered victims of bike theft are 10 a penny in the capital - almost 20,000 bike thefts are recorded each year in London, and more than 100,000 in the UK (countless more go unreported).

Soon after I decided to leave mainstream politics - I was the deputy chair of the Liberal Democrat Party - and concentrate on becoming an eco-auditor and writer, I looked around my home and realised that, like many a politician's property, it had suffered from years of neglect and now badly needed repairing and redecorating. Knowing that more than 72 million tons of waste is produced each year by the UK construction industry and that huge resources and CO2 emissions are involved in producing new building materials, I resolved that the refurbishment should be as eco-friendly as possible. I would avoid new products and, where I had to buy new ones, would opt for those with good environmental credentials.