Battle of Britain Sunday is a memorial day, held on the closet Sunday close to the Battle of Britain Day which was on the 15th of September 1940. A Sunday service is held at Westminster Abbey. Westminster Abbey will also fly the RAF Ensign flag on this day.
RAF Memorial on the Embankment
Central Church of the Royal Airforce St Clement Danes
Fleet Air Arm Memorial
Battle of Britain Memorial stained glass window at West Minster Abbey
Details about the Battle of Britain Monument can be found on its own website
A Memorial Service at Westminster Abbey took place 16th September