The 1920s building, designed by WA Williams, is at the centre of a bitter feud between developers and local heritage bodies, after being earmarked to make way for a new Wilkinson Eyre-designed transport interchange.
The County Court's decision to stop the case is the latest in a long line of disappointments for the development's opponents.
But one campaigner, Carlo Ambrosino, has vowed to carry his legal case on to the High Court despite demolition work being undertaken already, with the completion date set for 1 July.
Ambrosino will now take the case to the High Court in an attempt to win an injunction on any further destruction to the former electricity company headquarters.
The case hinges on a slight change in design to Wilkinson Eyre's tower. The number of rings on the 'busometer', according to Ambrosino, has jumped from 27 to 41 without a new planning application being gained.
A date has not yet been set for the High Court ruling.