English: The shield of arms of The Right Honourable Theresa Mary May, being the arms of her husband - Philip John May, son of Robert John May - differenced by a mascle.
Note: I have failed to find a blazon of her achievement, so this image is based on a photograph in the Daily Mail [1]. My best guess at the actual blazon of the arms is Or, a chief Vert, four roundels in bend between three pales Counterchanged. In the centre chief point a mascle Vert for difference. but I am hesitant to put that in the encyclopedia without a firm citation.