Sir John Fray was a lawyer who served as Lord Chief Baron of the Exchequer and had considerable experience of rivers and watermills.

Fray had the commission for maintaining the navigation of the River Lea around the years 1430–1440. He owned watermills in Essex and interests in other property across the country. These included Cowley Hall in Hillingdon

Hillingdon

Hillingdon is a suburban area within the London Borough of Hillingdon, situated 14.2 miles west of Charing Cross.Much of Hillingdon is represented as the Hillingdon East ward within the local authority, Hillingdon Council...

 which adjoined the Frays River

Frays River

Frays River is a river in England that branches off the River Colne at Uxbridge Moor and rejoins it at West Drayton.The Frays River leaves the River Colne between Uxbridge and Denham, Buckinghamshire at Denham Weir. It passes Cowley and Yiewsley where it is joined by the River Pinn. It is also...

. The Frays River is a branch of the River Colne

River Colne, Essex

The River Colne is a small river that runs through Colchester, England. It is not a tributary of any other river, instead having an estuary that joins the sea near Brightlingsea.-Source:...

which may have been developed to feed watermills in the area. It is said that John Fray arranged for the cutting of a link from the Colne to a tributary rising in Harefield to increase the water volume. .

He was also second husband of Agnes Danvers, and the grandfather of Sir William Waldegrave.