Easter Sunday falls on the first Sunday after the full moon following the spring equinox on 21st March. This unusual calculation, which uses a mixture of solar and lunar calendars, means that the day itself can occur anytime in a period of over a month - between 22nd March and 25th April. The next time it will fall this late will be in 2038 and you will have an even longer wait for a very early Easter. It will not take place on 22nd March until 2285.

Which is the most important clock in the world? Many visitors to London would answer ‘Big Ben,’ even though this is officially the name of the bell behind it rather than the clock itself. However, as a London blue badge guide, I would say that the world’s most important timepiece is the John Harrison H4 which can be seen in the Greenwich Royal Observatory museum near where the Prime Meridian is marked on the ground.