I went for drinks on Tuesday to Winfield House, the residence of the US ambassador in Regent’s Park.   It was assumed that I would know its architectural history, but didn’t.   It’s on the site of Hertford Villa, designed by Decimus Burton for the third Marquess of Hertford, known as the ‘Caliph of Regent’s Park’.   He is said to have used the house for orgies.   The original villa was damaged by fire in 1936 and the following year sold to Barbara Hutton, heiress to Woolworths.    A large neo-Georgian house replaced it.   It was designed by Leonard Rome Guthrie, a Scottish architect, who was the son of a Master Decorator and trained at Glasgow School of Art.   In 1925, he had joined the firm of Wimperis & Simpson, which had won the competition to design Fortnum & Mason, and in the 1930s he did work for the BBC, designing transmitter stations with art deco façades.