Why is the Gatehouse so special?
When Cardinal Wolsey began constructing his palace on the Thames in the 16th century, he chose to build in fashionable and expensive red brick, rather than stone. The brickwork was decorated with diamond-shaped diaper (criss-cross) patterns made from vitrified (burnt or glassy) bricks. In addition, this Gatehouse is decorated with Wolsey’s terracotta sculptures - known as roundels. 
The huge, gold astronomical clock was later installed by Henry VIII and remains one of the most significant late medieval clocks in Europe. The Anne Boleyn Gatehouse is one of the best preserved Tudor gatehouses in the country. Finally in 1707, Christopher Wren oversaw the installation of the bell lantern and cupola.

What is the problem?
The Victorians re-pointed the brickwork in a mortar containing black-ash, probably because it looked more in keeping with the historic character of the building. However, this mortar is hard and does not allow the building to ‘breathe’. In addition, areas of paint and gilding are flaking off the surface of the astronomical clock dials which have been exposed to the weather for almost 50 years since their last restoration.