The couple have chosen Langar Hall, an elegant country hotel in Nottinghamshire owned by a former Tory councillor who describes herself as one of Kenneth Clarke’s biggest fans.
A picture restorer turned hotelier, restaurateur and author, Imogen Skirving served on Rushcliffe Borough Council for around 10 years before giving it up after turning her family home into the business in the 1980s.
She admits that she would struggle to recognise Mr Miliband.
“I was in politics … Conservative of course, there’s no point being anything else around here,” she said.
Despite leaving the world of politics behind, she retains an admiration for her local Tory MP
“Ken Clarke, I love him, he’s the only person I rate in politics at all,” she said.
“I’m a big fan of Ken Clarke, he’s the best prime minister we never had.”
Built in 1837 on the site of the burned-down home of Admiral Lord Howe, one of Lord Nelson’s inspirations, the Hall itself has long political associations, although none of them Labour.
It was once the home of Thomas Bayley, Mrs Skirving’s great grandfather, a coal magnate and the Liberal MP for Chesterfield from 1892 to 1906.
Standing on the site of a Ninth Century pilgrims’ shrine, the Hall has no ghosts “at the moment”, jokes Mrs Skirving.
Its isolated location next to a 12th Century church outside Nottingham, has helped make it popular with celebrities as a quiet and low-key retreat.
Keira Knightley, the actress, and Jack Dee and Michael McIntyre, the comedians, are among recent guests while Sir Cliff Richard and the designer Sir Paul Smith are regulars, as was the late Dame Barbara Cartland.
Well known in the area for its restaurant, it is also a favourite for Miss Thornton’s family, only 20 minutes drive from her childhood home.
But despite the hotel's A-list clientele, the event, a ceremony and meal for about 50 people, is likely to cost the couple – who have yet to chose the menu – less than £3,000. Although the hotel will be closed to other customers for the wedding, the couple are not expected to stay the night.
Despite her true-blue credentials Mrs Skirving is sure the future Mr and Mrs Miliband will feel at home.
“He’s coming here as an individual, and every politician, or whoever they are, they are basically people at heart,” she said.
“When he comes here it will be a small informal wedding, very low key, that’s the sort if thing we do.
“The bit that I will enjoy is the security people, I always love anything like that, it just makes you feel important – never mind the next Prime Minister.