Royal aide Timothy Laurence, whose letters to Princess Anne have renewed speculation her marriage is in trouble, was dropped from Queen Elizabeth II's entourage at the public premiere of a new London musical.

But Buckingham Palace stressed in a statement that Laurence had remained on duty back at Windsor Castle, 21 miles west of London.The bachelor, a Royal Navy commander, had been scheduled to accompany the queen, Anne's mother, to a charity performance Monday night of composer Andrew Lloyd Webber's new show, "Aspects of Love," in London's West End.

As Scotland Yard investigated the theft of four of Laurence's letters to Anne from the palace, speculation about her 15-year marriage to Mark Phillips made front-page news again Tuesday in London's tabloids.

Phillips, a farmer and equestrian, is a former captain in The Queen's Dragoon Guards. Rumors his marriage to Anne is in trouble have circulated for years and recently the two have spent up to six months a year apart.

They have two children, Peter, 11, and Zara, 7.

Princess Margaret, Anne's aunt and the queen's only sister, was divorced in 1978 from Lord Snowdon, who has since remarried.