English Heritage is set to launch its own prosecution against the owners of Greenside, the Connell, Ward and Lucas Grade II-listed house demolished illegally last year.
The move comes after Runnymede District Council decided to delay any legal action. Council bosses are refusing to prosecute until they learn the verdict of a Department for Culture, Media and Sport public inquiry into whether the building merited listed-building consent. The inquiry is scheduled for November.
But EH is unhappy that legal action is now dependent on the inquiry and is considering whether sufficient evidence exists to launch its own prosecution against Greenside owners Gina and David Beadle.
An EH spokeswoman added: 'The inquiry and prosecution are separate issues. We have asked Runnymede to take action but we have received no definite response.'
The 1930s house had been at the centre of a conservation row since the Beadles secured listedbuilding consent from Runnymede last year.
Interventions by EH and the Twentieth Century Society convinced the ODPM to issue a holding directive against demolition. Despite the directive, the Beadles pressed ahead with demolition anyway.
Runnymede District Council head of law Andrew Gardiner insisted legal action at this stage would be premature.
'Irrespective of guilt or innocence, any judge is likely to want to hear the outcome of the inquiry before passing verdict, ' he said.