The earliest mention of Edge Grove appears to be around 1236, when the Abbot of Westminster granted one acre of land at Hemphegge Grove to Symon, Chaplain of Aldenham Village. Subsequent mention of it can be found under different names, but it is certain that the present house did not exist in any form until about 1740.

At about the end of the 17th century and the beginning of the eighteenth, various tenants’ names appear repeatedly, suggesting that there were several dwellings on the estate. There were also cottages down by the lake, which were demolished around 1705; and under the Aldenham Enclosure Act or 1801, seven acres of common land called Hedge Grove were enclosed.

Mr John Skey bought the property in 1733 and built the main block of the present house. His sons sold in the late 1780’s to Mr Thomas Hake who is believed to have built the bay window on the existing ballroom at the back of the house.

In 1912 John Pierpoint Morgan, an American millionaire, bought the property. He rented it to Mr Richard Bennett who effectively converted it into the shape it is today. We know that the clock tower was erected then. Finally, in the settlements of his estates in 1935, Pierpoint Morgan arranged for the county council to take over the freehold of the property, specifying that Edge Grove should be used as an independent school.

The school resulted in an agreement in 1935 between Captain Pratt and Mr Green (who together had a small boarding school called Parkfield) and Mr Waterfield (who ran what was then known as Radlett House, subsequently called Radlett Prep) to merge. There were initially about thirty boarders and thirty day boys.