We went down to the Post Office Railway, which opened in 1927 and operated until 2003. A 2ft narrow gauge, driverless underground railway built to transport mail between sorting offices.

In 1911 a plan was made to build an underground route to serve sorting offices as road congestion was causing unacceptable delays. Construction started in 1915. The main tube is at a depth of around 70 feet, it has a single nine foot diameter tube with two tracks which reduces to a single track seven foot diameter tunnel - not for those that suffer from claustrophobia. It was built for mail not people. Stations are at a shallower depth. It ran 6.5 miles from the Paddington Head District Sorting Office to Whitechapel, with eight stations, the largest underneath Mount Pleasant. The line became available for the Christmas parcel post in 1927 and letters from February 1928. The railway was closed in 2003. Tourist trains were installed in 2016 running a circular route beneath the depot at Mount Pleasant.

All aboard, said the conductor. We squeezed into our propagator-like carriages. The train set off at a fair pace, we were entertained by commentary, visual displays on the tunnel walls and an eerie couple of minutes of absolute darkness. Fifteen minutes later we arrived back for a wander around and play with interactive displays such as changing the points to ensure that trains didn’t crash into each other, sorting the mail on a wobbling train carriage and dressing up, however not in our usual sartorial elegance!!! On to the museum where we were able to see the new design for Charles III stamp.

Lunch at Luce e Limoni was delicious, with lots of chat and laughter.