From The Telegrpah:
"As the invitations to Prince William’s wedding drop on the doormats of the country’s best-connected households, one former member of the Royal family has been left disappointed.
Mandrake can disclose that Sarah, Duchess of York has not been invited to the ceremony at Westminster Abbey, at which her daughters, Princess Beatrice and Princess Eugenie, will be among the most prominent guests.
“She will not be attending the wedding,” confirms a spokesman for the former wife of the Duke of York. “She never expected to be invited or to attend. She will be overseas at the time.”