Betting on the Queen's abdication has been suspended after a large wager from the Windsor area raised questions of insider knowledge.
Bookmaker Coral had slashed the odds of Queen Elizabeth II stepping down before the end of the year from 3-1 to 1-2 before suspending the market yesterday after a £200 (NZ$394) bet was placed in Windsor.
A spokeswoman for the bookie said bets in that area were usually "spot-on", the Daily Mail reported.
A Buckingham Palace spokesman declined to comment, but the bet raised speculation of insider information and came at the same time as the 87-year-old monarch handed key responsibilities to Prince Charles.
"With her 88th birthday approaching, the Queen has started to relinquish a number of duties to Prince Charles, leading to major speculation about the monarch's future," the bookmaker's spokeswoman told the Mail.
The bookmaker's odds were 1-20 that Prince Charles would be next on the throne, while Prince William was being backed at 8-1.
The Queen's visit to the Normandy beaches this year, to mark the 70th anniversary of the D-Day landings, is rumoured to be her final official overseas engagement.
Royal aides have stressed the monarch is far from retiring.
She would be focusing on "behind the scenes" duties, they said.
With Prince Charles' shift to a more central role, the Queen would be able to concentrate on her role as head of state - including hosting foreign ambassadors and state visits.
Some the monarch's responsibilities have been handed to younger members of the royal family in the last few months.
The Queen's reign - since February 6, 1952, is the second-longest for a British monarch.
Only the 63-year reign of her great-great-grandmother, Queen Victoria, is longer.
The last English monarch to abdicate was King Edward VIII, who vacated the position in 1936 to marry American socialite Wallis Simpson.
Simpson was divorced from her first husband and pursuing a divorce from her second at the time.
The Church of England, which Edward was nominal head of as king, did not allow divorced people to remarry if their ex-spouses were still alive, so it was widely believed he could not marry Simpson and remain on the throne.
Widespread unwillingness to accept Simpson as the king's consort and Edward's refusal to give her up led to his abdication in December 1936 - the only British monarch to have voluntarily renounced the throne since the Anglo-Saxon period.