§ Lord Tebbitasked Her Majesty's Government:
When the practice of the spouses of Prime Ministers using notepaper headed "From the Office of (spouse's name and professional designation), 10 Downing Street" first arose. [HL4344]
§ The Lord Privy Seal (Lord Williams of Mostyn)The notepaper has been in use since 1997 to reply to those people who write to the Prime Minister's spouse in Downing Street. I cannot answer on behalf of previous administrations.