This summer marks 80 years since the Battle of Britain was fought in the skies over southern England. This was a fight for Britain’s survival against a Nazi Germany that had conquered much of western Europe in just a few short months. With the fall of France in June, Britain expected a German invasion, and one was indeed being planned under the codename Operation Sealion. However, for the invasion to be successful the Germans first needed to control the skies over Britain – they needed to destroy the Royal Air Force.

It's got to be one of London's best-loved events: from the arrival of the eagerly awaited annual catalogue and the feverish planning of visits, to that autumn weekend when the city flings open its doors to citizens and visitors. Yup, it's Open House - time for Londoners to get up close and personal with buildings they normally can't access.