Mr Livingstone's warning dramatically upped the stakes at the start of a week in which Mr Byers is expected to give the go-ahead for the controversial break-up. For the Mayor coupled his warning with a threat that, if the worst happens, the Labour Government will carry the entire blame. In doing so, he delivered Mr Byers the Black Spot. If the predicted disaster were now to happen, there is no way the Transport Secretary could keep his job and the entire Blair Government would be seriously damaged.