The Whitecross Tower, Tower 1 was added to the defensive medieval wall probably during the late 15th century, it is semi-circular in plan with an open back, with a battered ashlar plinth built against an earthern revetment.

Excavations in the city ditch were undertaken in June 1968 with the aid of a grant from the Ministry of Public Buildings and Works, in advance of the Pin Hill/Rhodaus Town road widening scheme, to investigate the ditch and the foundations of the city wall. The site of the excavations, immediately to the west of the White Cross Bastion, was chosen because landscaping there had been less drastic than in other parts of the ditch.
However, nearly all levels later than early Roman were found to have been removed from the bank, and the stratigraphy was further disturbed by a recent garden wall and an electricity cable that ran across the site. Two main trenches were dug across the ditch at right angles to the wall, Trench II in the angle of the White Cross Bastion and the wall, and Trench I 26.82m to the west of this. A Mechanical excavator was used to cut the main ditch section in Trench II and those parts of both trenches relating to the bank and wall were dug by hand.
A complete half-profile from the wall to the centre of the ditch was obtained. The lip of the ditch was 3.05m from the base of the wall and the profile of the ditch sloped at an angle of 40 degrees to reach its deepest point 10.97m from the lip and 5.49m below it. The ditch was cut successively into natural brickearth, gravel and chalk. The greater part of the fill was clean brown silt, presume to derive from the brickearth and quite sterile, though one Roman sherd was found within it. Towards the bottom of the ditch, the fill became greyish and waterlogged and showed some signs of organic remains. This section agreed quite well with the sections shown in bore hills drilled for the city engineer in the St George's Gate areas of the ditch.

The foundations of the wall were trench built of irregular coursed flints set in rather soft buff mortar and they extended to a depth of 0.76m below the modern ground level. The foundations of the White Cross Bastion were three offset courses of large chalk blocks set in yellow mortar. Both foundations were laid directly on the natural brickearth. A certain amount of construction debris consisting of chalk and mortar rubble was found against and oversailing the offset of the foundation in trench I, but it contained no dating evidence. 1st and 2nd century rubbish pits were found to cut into the brickearth and produced a fair amount of pottery.

Millard, L. & Jenkins, F., 1968, Excavations in Canterbury City Ditch (Unpublished document). SKE30758.

Millard, L., 1970, Canterbury City Ditch (Serial). SKE30757.

Austin, R., 2001, Personal Comment Rupert Austin, Inventory List (Unpublished document). SKE29779.