It is not known why Norris built the tower, although a number of theories have been advanced, including that it was a watchtower guarding against highwaymen on the nearby road; that it was a beacon guiding travellers on the heath to safety; that it was a viewing platform for watching the local foxhunt; that it was a signalling tower; or that it was simply a folly with no purpose.

The most widely held theory is that the tower was used by Norris for signalling to his good friend, Sir Francis Dashwood (1708–1781), who lived in West Wycombe, Buckinghamshire, close to Norris' second home at Hughenden Manor.
In 1751 Dashwood had built a hollow wooden ball covered with gold leaf, 8 feet (2.4 m) in diameter, with wooden seats for several people inside, on top of the tower of St Lawrence's Church at West Wycombe.
The church tower was 21 miles (34 km) north of Norris' tower, and it is claimed that the two men signalled to each other from the top of the two towers, either using flags or heliographs (which make signals by reflecting sunlight).
Some sources suggest that Norris' tower originally had a golden ball on top of it, matching the one on the West Wycombe church tower, but this is not shown in early pictures of the tower.

Various reasons have been put forward to explain why Dashwood and Norris needed to signal information between themselves.
It has been speculated that the two men signalled bets to each other, or that the signalling was related to the activities of the disreputable Hellfire Club that both men were members of.
It has even been suggested that they were involved in an espionage network, and that during the period of the American War of Independence Norris passed secret information to Dashwood, who was Postmaster General from 1765 to 1781.
This theory is supported by a letter written by Norris, dated 3 June 1778, in which he notes: "Did this day heliograph intelligence from Dr Franklin in Paris to Wycombe".
It is not known why Norris built the tower, although a number of theories have been advanced, including that it was a watchtower guarding against highwaymen on the nearby road; that it was a beacon guiding travellers on the heath to safety; that it was a viewing platform for watching the local foxhunt; that it was a signalling tower; or that it was simply a folly with no purpose.
The most widely held theory is that the tower was used by Norris for signalling to his good friend, Sir Francis Dashwood (1708–1781), who lived in West Wycombe, Buckinghamshire, close to Norris' second home at Hughenden Manor. In 1751 Dashwood had built a hollow wooden ball covered with gold leaf, 8 feet (2.4 m) in diameter, with wooden seats for several people inside, on top of the tower of St Lawrence's Church at West Wycombe. The church tower was 21 miles (34 km) north of Norris' tower, and it is claimed that the two men signalled to each other from the top of the two towers, either using flags or heliographs (which make signals by reflecting sunlight). Some sources suggest that Norris' tower originally had a golden ball on top of it, matching the one on the West Wycombe church tower, but this is not shown in early pictures of the tower.
Various reasons have been put forward to explain why Dashwood and Norris needed to signal information between themselves. It has been speculated that the two men signalled bets to each other, or that the signalling was related to the activities of the disreputable Hellfire Club that both men were members of. It has even been suggested that they were involved in an espionage network, and that during the period of the American War of Independence Norris passed secret information to Dashwood, who was Postmaster General from 1765 to 1781. This theory is supported by a letter written by Norris, dated 3 June 1778, in which he notes: "Did this day heliograph intelligence from Dr Franklin in Paris to Wycombe".
Camberley Obelisk