The Countryside Alliance, which has been campaigning against a ban on hunting, last night distanced itself from the letter, claiming it was not "official". The Alliance has written to Shooting Times, the bible of the blood sports fraternity, making clear it is not responsible for the letter.
But the chain letter already claims to have the support of 100 leading politicians, businessmen and society figures including Prince Nicholas von Preussen, Sir John Paul Getty, the Earl of Pembroke, the Marquess of Douro, and the Duke of Beaufort.
The move comes as Tony Blair announced his intention to ban fox hunting before the general election. He surprised MPs and delighted anti-hunting campaigners last week by announcing on BBC's Question Time that fox hunting "will be banned; we will get the vote to ban as soon as we possibly can".
The anti-hunting lobby has threatened to "fiercely resist" any move to ban hunting. But animal welfare groups said that any attempt to influence opinion poll phone-ins on hunting would not work.
"All the official polls show massive public opposition to hunting among country people no less than those who live in towns," said Richard Ryder, a member of the RSPCA council. " I have lived in the countryside all my life and I know that most real country people quite frankly find hunting cruel and a nuisance. Any attempt to influence the results of a poll is a sign of failure."
The Countryside Alliance believes that the opinion poll letter is being sent by an anonymous supporter who is well connected among the hunting fraternity. In its letter to the Shooting Times the Alliance urges recipients to help them to "discover who started the chain".
"We don't know who has initiated this," said a spokesman for the Countryside Alliance. "We have tried very hard to track down where this comes from. We think it is a wonderful whizzy idea but it is actually not any use to us."
The letter has been circulating via the post for the past few months and has recently been put on the e-mail system. The letter, entitled British Field Sports Society/Countryside Alliance Organisation for Response to Field Sports Survey, urges hunt supporters to "turn the tables" on "a well-organised campaign against us "through sheer weight of numbers."
It is followed by a list of well-known hunt supporters whom it claims have already been contacted including Baroness Mallalieu, the Labour peer.
The Countryside Alliance confirmed that the list included leading supporters of field sports but could not confirm they were part of the chain.
SIR JOHN PAUL GETTY
Billionaire philanthropist who adopted British nationality. Probably Britain's single biggest charitable donor, thought to have given at least pounds 120m to British causes. View on hunting: "I think hunting should be preserved. It's best to do these things the country way."
High-profile supporter of the pro-blood-sports lobby, leader of the Labour Party's Leave Country Sports Alone group and President of the Countryside Alliance. Last autumn led unsuccessful attempt to overturn the National Trust's ban on stag hunting on its land.
SIR ROCCO FORTE
Chairman of RF Hotels Ltd and son of Lord Forte, who lists his interests as fishing, shooting and fencing. Featured in BBC2's Blood on the Carpet, which told the story of Granada's corporate assault on Forte. Recently signed up to back a no-vote in any referendum on the euro.
SIR CHIPS KESWICK
Director of Bank of England since 1993 and senior banking and capital markets adviser for Societe Generale. Director of De Beers Consolidated Mines and Persimmon, the house builders. Lists his recreations in Who's Who as bridge and country pursuits.Reuse content