The big switch off will happen on 3 August and last approximately three weeks while the wireless network is upgraded to use 720 x 576 pixels instead of the current 704 x 576. Some of the areas affected are Oxford Street, Belgravia, Trafalgar Square and Knightsbridge. The DfT ruling came in on 1st April and Westminster were the fools of the day - despite being part of the initial task force responsible for the ruling, they didn't manage to spot the change.
Worse, the upgrade could mean the loss of archived footage, anyone with an outstanding appeal against Westminster faces the loss of evidence, though given the council has set themselves a target of 736,000 tickets to be issued over the next year, we're willing to bet they'll press on with prosecutions.
Rest assured though, central London won't become a parking free-for-all; Westminster have said they will lay on extra parking wardens to
ensure ticketing targets are met keep the streets safe.