Labour claims the seamy campaign technique, called "push polling", was first used in Britain in the recent Wirral South by-election. It was used in the election in Australia last year by the right-wing Liberal Party, which went on to win.
First used in the US, push polling entails telephone calls or questionnaires sent to voters under the guise of bona fide opinion polls. At the end of the call, or in the survey document, the voter is hit with a damaging claim about a rival candidate.
Andrew Robb, federal director of the Liberals and the man at the centre of the row in Australia about push polling, came to Britain late last year to advise the Tories on campaign strategy. He was joined by Mark Textor, the Australian Liberals' chief pollster in their 1996 campaign.
The cooperation pact between the Australian and British parties was sealed on a visit by Brian Mawhinney, the Tory chairman, to Australia last October.
During his trip, Mr Mawhinney attended a dinner hosted by Ron Walker, the Liberals' federal treasurer and prime fundraiser. Mr Walker is a heavyweight business and political figure in Australia. He was instrumental in securing the transfer of this weekend's Formula One Grand Prix from Adelaide to Melbourne.
After Mr Mawhinney's visit, Mr Robb and Mr Textor came to Britain to advise the Tories. Mr Walker said they were sharing the Liberals' successful campaign tactics with their British counterparts. The two men have since returned home.
In Australia, defeated Prime Minister Paul Keating referred to push polling's use last year as "one of the most appalling and sinister developments in Australian politics". He was speaking after the Liberals were accused of inserting false statements about a Labor candidate into a questionnaire sent out by the Roy Morgan Research Centre, where Mr Textor used to work.
Mr Robb defended the poll, saying that the Liberals "asked questions we understood to be true". The Labor candidate issued writs for defamation against Mr Robb and the research centre.
In Britain, before the Wirral South by-election, a polling firm sent a questionnaire to local estate agents. One of the questions asked how house prices were affected by the presence of a nearby grammar school. Thesurvey found that prices rose the nearer houses were to the school, and the results were printed in a local newspaper. Then, in unsolicited calls to voters, the Tories quoted from the newspaper.
"Voters were asked if they lived near the school, which of course they did," claimed a Labour Party spokesman. "Then they were told how much more their house was worth. Then they were asked if they knew that Ben Chapman [the Labour candidate] planned to shut it - which was not true - and how they felt about that."
This, he said, was the first instance Labour had come across of the US- Australian device. "You soften people up and have a good chat, and then at the end, bang, you hit them with something nasty about the other side," said the Labour official. Labour, he added, would not do push polling. "We are more up-front about what we do."
A senior Liberal source in Melbourne said that the Liberals and Tories were working together and had developed close contacts.
In Canberra, Mr Robb declined to comment on his work for the Tories. "Anything the Conservative party has learned from us is their business. It's up to them if they want to discuss it. It's not up to us."
A Tory spokesman said the Conservatives had no plans to use push polling. He could not discuss in detail Mr Robb and Mr Textor's advice to the party.
Mission Impossible, page 6