This was the date that Philip eventually signed a Deed of Gift to the Trust. Valued at three million pounds, the deed included the house, furniture, 1,964 acres of land, 14 farms and several houses and cottages in Wrexham and Ruabon, all of which had been part of Phillip's personal estate.
A supplemental agreement was made the same day, in which the Trust had also to agree to continue the Yorke custom of allowing the grounds to be used for fox hunting, camping and other boy scouting activities. The National Coal Board offered to pay £120,000 compensation to the Trust for the damage caused by mining.63 acres of Erddig Park was subsequently sold for £995,000 which paid for restoration work on the house, which was completed when the Prince of Wales officially opened the house to the public on 27 June 1977.
Going back to February 1970, when the National Trust was negotiating with Philip Yorke on the takeover of Erddig, the Trust produced a financial report on the cost of restoration and maintenance. An approximate figure of £800,000 was finally proposed for an endowment, and was met with an incredulous reaction from Squire Yorke, even though it turned out to be a serious underestimate. Singled out for particularly strong criticism was the proposition that two of the lodges should be restored and occupied by staff in order to offer some protection against the vandalism prevalent in the Wrexham area:
“My brother always liked the idea of a lodge-keeper smoothing out a clean apron whenever she heard the sound of horses’ hoofs and dropping a curtsey as the carriage went by, but in these days a cattle grid is regarded as more practical.”
The very thought of putting Erddig on the mains appealed even less:
“I know little of main water excepting that it is not as cold as ours and the farmers don’t like it for cooling the milk. It often has a brown colour and is largely made up of disinfectants.”
He accused the Trust of “carefree abandonment of reason and accuracy when dealing with other people’s money” and there was ominous talk of giving everything to the Welsh Nationalists.