Rolling Stone Mick Jagger joined more than 200 celebrities in signing a letter calling on voters in Scotland to reject independence in a referendum next month.

Actress Judi Dench, cosmologist Stephen Hawking, television presenter David Attenborough and evangelical atheist Richard Dawkins joined Jagger in putting their names to the "Let's Stay Together" campaign to retain the 307-year-old union with England.

"The decision on whether to leave our shared country is, of course, absolutely yours alone," the celebrities said. "Nevertheless, that decision will have a huge effect on all of us in the rest of the United Kingdom. We want to let you know how very much we value our bonds of citizenship with you, and to express our hope that you will vote to renew them."

The letter, coordinated by TV historians Dan Snow and Tom Holland, is the latest attempt by the "no" campaign to halt the Scottish National Party's drive for independence. Scots will vote on Sept. 18 to decide whether they should cut ties with the rest of the U.K.

A gambler extended a £400,000 ($673,000) bet on a "no" vote in the referendum to £600,000, bookmaker William Hill Plc said in an emailed statement today. The punter, who's not Scottish and laid the bet at a shop in Surrey, south of London, stands to collect 733,333 pounds if independence is rejected.

Former Chancellor of the Exchequer Alistair Darling, who leads the "no" campaign, and SNP leader Alex Salmond clashed in the first of a series of televised debates this week as polls show a continued lead for opponents of independence.