On 17 January in another accident involving a member of the UK royal family, the Duke of Edinburgh, 98, flipped his Land Rover Freelander after colliding with a car at the Queen's retreat, Sandringham.

An elderly woman is reported to be in grave condition after an accident involving the Duke and Duchess of Cambridge's motorcycle escort, reports Sky News.

Kensington Palace said the royal couple had sent flowers to the woman, and are “deeply concerned and saddened” by the incident.

The accident took place at about 12.50pm on Monday in Richmond, southwest London, and involved a motorcycle attached to the Royalty and Specialist Protection Command.

Prince William, 36, and Kate Middleton, 37, accompanied by the motorcycle escort, were heading to Windsor for the St. George's Chapel service commemorating the Order of the Garter.

Irene, as reports refer to the victim of the accident, was rushed to hospital, where the 80-year old remains in a serious but stable condition.

The collision is currently being investigated by the Independent Office for Police Conduct (IOPC).

An IOPC spokesman said: “The woman, in her 80s, suffered serious injuries and was taken to a London hospital where she remains in a serious but stable condition.”

"Our staff attended the scene of the incident and after careful consideration, we have launched an independent investigation.”

“The investigation is in its very early stages and the officer involved is assisting our enquiries as a witness.”

“Our immediate thoughts are with the injured woman and her family and those affected by the incident.” “Their Royal Highnesses have sent their very best wishes to Irene and her family and will stay in touch throughout every stage of her recovery.”