English Heritage is preparing to interview 'under caution' the owners of Connell, Ward and Lucas' Greenside following the illegal demolition of the Grade IIlisted property last year.
The conservation quango will use its statutory powers to record the interview as evidence to use 'in a court of law'.
The interview forms part of a concerted campaign by both EH and the Twentieth Century Society to secure a full legal prosecution against Gina and David Beadle.
The couple triggered outcry in November after they ordered the building to be knocked down despite a holding directive against the demolition order secured from Runnymede District Council.
The Beadles have spent the intervening months in South Africa away from the controversy but are set to return this Saturday (28 February). The AJ understands that the couple have agreed to give the interview when they arrive.
However, a spokesman for EH said its South East Region officers would continue to gather evidence for a prosecution 'even if the owners refuse to be interviewed'.
'We originally agreed to carry out the interview in December of last year but they then changed their minds, ' he said. 'We hope they will attend this time round.
'We have to gather the evidence to prove that an offence has been committed. We need to show that it was illegal to demolish the building and prove that they were the ones that ordered it.
'Even if the Beadles fail to cooperate, we will remain determined to find enough evidence to go ahead with the case, ' he added.
The Twentieth Century Society's caseworker, Claire Barrett, said the interview would be key to a successful prosecution.
'It is important that EH carry out the interview with a full caution to the owners and make sure it is recorded on a tape recorder, ' she said. 'This will be essential to take the owners to court.'