Seen to be done

Who said "Justice must not only be done; it must be seen to be done"?

According to the Penguin Dictionary of Modern Quotations,it was somebody called Lord Hewart, about whom I know nothing. (Could be a senior judge: the top judges in Britain, the "law lords" get peerages). The exact quotation is given as "...justice should not only be done, but should manifestly and undoubtedly be seen to be done".

Gordon, Lord Hewart, Lord Chief Justice 1922-1940. Admired by some, the opposite by others.