Members of Labour’s ruling executive committee, on which Tony Blair sits, approved the payment from a charity which is closely linked to the Church of Scientology, which boasts Hollywood stars Tom Cruise and John Travolta among its members.
Tory bosses also sanctioned a stand at their annual gathering in Bournemouth.
But MPs expressed concern after it emerged that they were part of an extensive lobbying operation by Scientology members to promote its drug treatment programme, Narconon, and the criminal rehabilitation scheme Criminon.
The “religion” founded by science fiction writer L Ron Hubbard, was once branded “corrupt, sinister, immoral and dangerous” by High Court judge Mr Justice Latey.
The Home Office has refused to sanction Narconon because it “does not meet the minimum standard for drug treatment delivery. It has never been funded by the Prison Service.”
But papers released under the Freedom of Information Act reveal that Graeme Wilson, the chief UK spokesman for the Scientologists, met Baroness Scotland – then a Home Office minister – in Manchester.
Liberal Democrat MP Norman Baker said: “Scientology is a dubious cult at best and it’s worrying that it seems to have infiltrated both Labour and the Tories in this way. It only goes to show that some politicians are prepared to take money from anyone. Given Scientology’s record of spin it is no surprise that they have links to this Labour Government.”
A Labour spokesman insisted that the payment was a business transaction and did not constitute a donation to the party. He added: “Approval for organisations looking to attend conferences is made after careful consideration by the NEC board. We do reserve the right to exclude an organisation but in this case approval was given. Every year exhibitors represent a range of views and opinions. Their policies may not always reflect those of the Labour Party.”
A Tory spokesman said: “Many organisations rent space at our conference to exhibit. Like Labour we reserve the right to exclude an organisation. In this case we allowed Narconon to rent a stand to exhibit their work on drug rehabilitation.”
Critics of Narconon claim it is a front for Scientology. The programme, which uses Mr Hubbard’s teachings to help wean addicts from drugs, is funded by £15,000 payments from participants for a six month course. But the website for ABLE, the charity behind it, admits they “receive much support from Scientologists and from churches of Scientology”.
A spokeswoman for the Church of Scientology claimed that the treatment programme, which makes patients go “cold turkey” has a 75 to 80 per cent success rate.
But in 2001 London Mayor Ken Livingstone banned the Scientologists from promoting it at an event in Trafalgar Square. He dismissed it as “a medically unproven policy which I am advised could be dangerous’ and ‘a spurious medical programme which many drugs professionals are concerned about.”
Former Tory minister John Gummer said the Home Office should have nothing to do with Scientology. He said: “They have often presented their views under the cover of some kind of charitable exercise. Those who are the most vulnerable should be the most protected.”
The revelations came after the Daily Mail revealed that Scientologists infiltrated the City of London police handing thousands of pounds worth of gifts to officers. The group – which is worth £200million worldwide – handed out free invitations to film premieres and a £500a-head charity dinner where the guest of honour was Tom Cruise.
The Charity Commission in Britain has refused to register the Church of Scientiology, which has faced repeated claims that new members are manipulated and enticed into spending thousands of pounds on Scientology courses.
In 1994 the Californian Court of Appeal accepted that the techniques of Scientology constitute “brainwashing” and “thought reform”.
A Scientology spokeswoman said: “Making our programmes and work known to the various members of parliament and their staff is a responsibility of ours.
“Internationally Narconon now runs 184 centers across 44 nations. Contrary to current propaganda, Narconon is completely scientifically based.
“There are many people in the Home Office who haven’t taken the opportunity to take a tour of Narconon and hence the discrimination from the propaganda of the past still lingers.
“There is only one staff member at Narconon who is a Scientologist. It is a secular programme and they take anyone from any religion or none. They do not preach any religion and have a policy against discussing religion with any student.
“None of the graduates have become Scientologists, but if they had, that would be their choice. To imply there would be something wrong if they did is off the wall.”