This four storey tower by the north corner of the North wing was built in 1851. The windows to the front and rear of the Tower match those added by Wyatt but those on the North West face appear to be 18th century sash windows. In fact the Tower covers part of the North wing built in the 18th century. Two redundant windows were taken from there and placed on the two top floors of the Tower whilst the first floor window was constructed to create a matching set. The ornate door at the foot of the Tower also comes from the earlier building. The arms and crest mounted over the door record the marriage of William Towneley and Cecilia Standish in 1736.
The Military Room is on the ground floor and the Towneley Room on the first floor. On the second floor is a store room for oil paintings, named the Top Oil Store to distinguish it from the Large Oil Store on the first floor of the North wing. On the top floor are stores for the Natural History collections.
In 2001, a lift was installed for those not able to use the back staircase.Whilst the outside of the North wing was essentially unchanged by the addition of the new wing in 2001, there was a change to the Victorian tower itself. This was the addition of an emergency exit door close to the lift