The complicated system set up to charge motorists entering the city of London is generating almost as much revenue from those who don't pay the £5 (US $9) charge as from the charge itself. Cameras send £100 citations to those who fail to pay the tax, as several London motorists recently found when they followed signs diverting traffic off of temporarily closed Tower Bridge.

The latest figures show that 108,000 pay the charge daily, generating £540,000 (US $981,000) in revenue. Yet, every day, London's system mails 6,600 motorists a fine for failing to pay the tax, for a total bill of £660,000 (US $1.2 million). So far, however, only 71 percent pay their tickets so that the city actually collects £468,600 each day.

Beginning July 1, the congestion charge jumps to £8 US ($14.50) for each visit, so that the city will pocket a combined daily tax and collected ticket revenue of £1.3 million (US $2.4 million).