A row has broken out over a trip described as 'educational' to Budapest and Paris by the heads of most of Britain's cancer charities that has been funded by a major drugs company.

Sanofi Aventis has arranged for policymakers and patients' representatives to enjoy a weekend away while they get the chance to hear about new cancer drugs, many of which are not yet offered by the NHS.

A draft of the itinerary, leaked to The Observer, describes the meeting as a 'parliamentary and stakeholder working group'. It began yesterday morning with a flight to Budapest and incorporated the opening of the European Association of Cancer Research conference. There was 'optional attendance' at the lectures and an exhibition, followed by a dinner. Today the participants were going to a hospital in Paris where they were seeing the 'gold standard' treatment received by French patients in contrast with that experienced by NHS patients.

The most senior cancer official within the Department of Health is attending, although her costs are being met by the government, and two MPs are going on the trip, courtesy of a Westminster firm of political lobbyists. However, Dr Ian Gibson, chairman of the all-party parliamentary group on cancer, declined the invitation. The Labour MP for Norwich North said: 'I didn't want to go because it was funded by a drugs company. There are other ways of finding out how other countries' cancer plans work without taking a weekend in Budapest and Paris. If I want to learn more about a particular cancer therapy, I can talk to doctors here who know about it. I really feel that these charities should pay for themselves - or if they can't, the company should hold the whole meeting in London.'

One insider who saw the draft itinerary said: 'This kind of trip gives the company a chance to point out that other countries are spending more on new cancer drugs than the NHS. What it does is give charities the ammunition to go back to the UK and say, well, the French are prescribing this new drug, so why is it being denied to our patients?'

The charity bosses defended their roles. Mike Unger, head of the Roy Castle Lung Cancer Foundation, said: 'We've fully discussed this trip with our trustees and the board, and felt it was of value. If we paid, then it would come out of the charity's fund for research, which would be very wrong.'

But there is growing concern about how 'Big Pharma' is influencing patients' groups. The medical journal the Lancet called last week for greater transparency from the charities over where their sponsorship money came from.

Cressida Ward, the communications director for Sanofi Aventis, said: 'This is a purely educational trip. It enables the MPs and the patients' groups representatives to look at best practice that is happening; I can't see the harm in this.".