The Queen has been forced to cancel a planned visit to Chelmsford because of her recent knee operation.

She had been due to attend a special service at the cathedral on 31 January to mark the 50th anniversary of the floods in eastern England in which 300 people died.

The Queen is recovering from the surgery and the day would have involved large amounts of standing and walking.

The Earl and Countess of Wessex will attend the service - followed by a lunch at County Hall - in her place.

Minor operation

A spokeswoman for Buckingham Palace said: "Clearly it's a significant local occasion, but sadly the Queen will not be able to attend."

The Queen left the King Edward VII Hospital on Tuesday following an overnight stay for the minor operation to remove cartilage from her right knee.

She had sustained the injury during a private visit to Newmarket just before Christmas.

The 76-year-old monarch is now convalescing at Sandringham in Norfolk.

Another official engagement at Sandringham on 29 January will go ahead as planned, but further changes may have to be made to her programme in February.

The 1953 floods are said to be the worst peacetime disaster in Essex, where 119 people died.

Survivors and those who helped in the clean-up operation are due to attend the service.