Start on A45 (Dunchurch - Daventry road) at corner of road leading to Onley prison, 1 mile south east of Dunchurch
Proceed south east along A45 to island junction with A361. Take 2nd exit and continue along A45
Proceed to island fornerly known as "British Timken" island.
Encircle island and retrace
along A45 to Finish in line with first edge of rectangular manhole cover in
107 yards short of the start. (marked)