“The Queen has been forced to cancel an engagement today as she is feeling unwell. I understand there is no cause for alarm. She is not being attended by a doctor and will go to Windsor as planned this afternoon. Her programme of events will go ahead in Scotland next week.”

BP say: The Queen is feeling under the weather today and has decided not to attend this morning’s service at St Paul’s Cathedral marking the 200th anniversary of the Order of St Michael and St George. Her Majesty will be represented by The Duke of Kent as Grand Master of the Order.

Rebecca English on Twitter