Fight them on the beaches if you will. But the descendants of Sir Winston Churchill have decided that a more effective way to prevent the Church of Scientology from hijacking the memory of Britain's wartime leader involves stern cease-and-desist letters and the threat of a costly PR battle.

In an unlikely dispute that pits Sir Winston's grandchildren against followers of the late L Ron Hubbard – the science-fiction writer who believed, among other things, that mankind descended from aliens who arrived on Earth via spaceships – the controversial church has been asked to remove Churchill's image and quotations from its fundraising literature.

The literary agency Curtis Brown, which represents several members of the Churchill family, has written to the church's London branch protesting at a range of advertising leaflets and posters that liken the Allied struggle against Nazi Germany to Scientology's efforts to recruit new members.

Download the new Independent Premium app Sharing the full story, not just the headlines

One image, seeking new staff to volunteer to work at the organisation's headquarters, carries a black-and-white picture of a Spitfire soaring triumphantly over the Home Counties, together with the quotation: "It's not enough that we do our best. Sometimes, we have to do what's required." Another, to advertise a fundraiser to help the church create a celebrity centre in London, similar to the one it already has in Hollywood, name-checks Churchill among such "Great Britons" as David Beckham, James Bond, Harry Potter, The Rolling Stones and The Beatles. The leaflet claims the event will be "their finest hour".

Although the adverts may seem like a harmless (if somewhat crude) attempt to use these images for the purposes of publicity, Sir Winston's descendants are highly upset. The former prime minister's grandson and former Tory MP, also named Winston Churchill, said that he finds them "obnoxious" and "offensive." "Gordon Wise at Curtis Brown has written the Scientologists a letter protesting, on my instructions. Predictably, nothing has been received in return. The family finds it very offensive that an organisation not only as controversial, but some might say as disreputable, as the Church of Scientology should be trying to use my grandfather's likeness and quotes in furtherance of their recruiting.

"We have strong objections to the implication that our grandfather, if he were alive, would have something to do with Scientology. In fact, he wouldn't have touched an outfit like that with a bargepole. I can't represent too strongly how much we resent the suggestion that he would. They have no right, or permission, to use his name or likeness, and I hope they now respect my grandfather and his family's wishes."

Sir Winston was, as it happens, a member of the Church of England, and married in an Anglican church. However, by the standards of his time, he was not thought to have too much time for any religion, and once jokingly cautioned: "It is never wise to prophesise until after the event as taken place."

The Church of Scientology did not respond to requests for comment about the leaflets. However, when Sir Nicholas Soames, another grandson of Sir Winston, complained about them earlier this month, a spokesman argued: "The use of iconic images, including those available in the public domain, to add colour is, of course, done very commonly."

Whatever the eventual outcome of the dispute, it has been a tricky few months for Scientologists. A court in France, where it is classified as a sect, convicted it of defrauding followers of thousands of euros and gave its leader there, Alain Rosenberg, a €30,000 fine and suspended two-year prison sentence.

Meanwhile, in Hollywood, the organisation's spiritual home, it was rocked by the resignation of Paul Haggis, the Oscar-winning producer of Crash, who wrote a widely leaked letter condemning its methods.