Britain's Queen Elizabeth will attend a lunch at 10 Downing Street today (24.07.12).
The monarch will dine with four Prime Ministers who have served her, Gordon Brown, Tony Blair and Sir John Major, as well as the present incumbent David Cameron, who has invited the queen and Prince Philip to the event as part of her Diamond Jubilee celebrations.
But Margaret Thatcher, who served the royal between 1979 and 1990, is not planning to attend after largely withdrawing from public life.
The prime minister's wife Samantha will also be present at the meal along with Sarah Brown and Lady Major, but Cherie Blair is unable to attend as she is travelling.
A spokesman for Blair told the Daily Telegraph newspaper: "Mrs. Blair had hoped to go but she is working on a legal case out of the country so is unable to attend."
Cameron gave a reading at a service of thanksgiving at London's St Paul's Cathedral last month to mark the end of four days of celebrations across the UK for the queen's Diamond Jubilee.
Other attendees included the queen, Prince Charles, the Duchess of Cornwall, Princes William and Harry and William's wife Duchess Catherine but Philip was absent after being hospitalised in early June with a bladder infection.