One of the scarcest political covers ever issued to commemorate the 40th anniversary of Margaret Thatcher becoming leader of the Conservative Party in 1975. The first woman to lead a British political party. The important cover bears British Margaret Thatcher stamps with Royal (Royal Mail) "Iron Lady" Grantham Prime Minister pmk. dated 14/10/2014 as well as the scarce Big Ben Anniv. postmark dated 11/2/2015. This cover which is mostly in collectors' hands is rarely offered for sale.