This tower is part of the wall of St Mary's Abbey. It was built by Stephen de Austewyk in 1324 as a tall, circular tower, 10 metres in diameter and over 10 metres high.

Little is known about the tower until 1644 when it was the subject of a heavy attack by the Parliamentarians. On the 16 June a mine exploded underneath the Tower. Troops entered and got as far as the King's Manor but were then beaten back with 216 captured and 40 killed.

After the Civil War the tower was clumsily rebuilt with thinner walls on the outside but kept the octagonal shape on the inside.

Today the tower has been restored and is currently used by the Da Costa Academy who teach singing.