The tower was closed to visitors in 1975 for major construction work and was under-pinned to prevent subsidence, but instead of reopening to visitors, it was later converted into office space for the Royal Archives.
But over the summer months, visitors to the landmark, which has dominated the Berkshire skyline for more than 800 years, will be able to walk up its 200 steps to the top of the structure.
A new ‘Conquer the Tower’ tour will include a visit to the external ‘gallery’ at the base of the tower’s drum, where bowmen were stationed in Medieval times as an additional defence for the Castle.
Now known as the ‘cannonade’, the gallery is equipped with 16 18th Century bronze field guns mounted on cast-iron carriages.
Then when visitors reach the top of the tower they will be able to enjoy views across Windsor and the London skyline from their position 65.5 metres above the River Thames.
Tourists will also be able to climb to the roof of the tower for a close-up view of the castle’s 15-metre flagpole, which flies the Royal Standard when the Queen is in residence and the Union Flag when she is not at Windsor.