An audiotape the Liberals were hoping to use in the election campaign has been effectively silenced by delays in a court hearing into the Cadman affair.

Prime Minister Stephen Harper won an adjournment Wednesday, putting off the hearing into his motion for an injunction to prevent the Liberals from using the audiotape at the centre of bribery allegations in the Cadman saga.

While the judge did not set a new date for the hearing, which was to have started Monday, the Liberal party's lawyer acknowledged there's now no chance that the case will heard before the Oct. 14 election.

The Liberals have not used the tape since Harper sought the injunction last June — and party officials say they won't as long as the matter is still before the courts.

The tape is at the heart of Liberal allegations that Harper was aware of a Conservative attempt to bribe Chuck Cadman, the late independent MP, in return for his support during a crucial 2005 confidence vote.

The allegations prompted Harper to launch a $3.5-million defamation suit against the Liberal party.