The monarch, 95, has rallied to make an appearance and lead her family at the high-profile and personally significant occasion in honour of husband Philip.
A Service of Thanksgiving for the Duke of Edinburgh will be a personal tribute from the Queen to her husband after she insisted on being actively involved in elements of the event.
Prince Philip's memorial service: Order of service - Gloucestershire Live gloucestershirelive.co.uk - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from gloucestershirelive.co.uk Daily Mail and Mail on Sunday newspapers.
The PM and his wife Carrie (pictured, in Sussex over the weekend) are set to join a congregation of 1,800 people as they gather at Westminster Abbey today.
Why Prince Harry and Meghan Markle are not at Duke of Edinburgh memorial service birminghammail.co.uk - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from birminghammail.co.uk Daily Mail and Mail on Sunday newspapers.