US presidential candidate hails Baroness Thatcher

US presidential candidate Mitt Romney hailed Margaret Thatcher as a "tower of strength in the cause of liberty" as the former prime minister celebrated her 87th birthday.

Baroness Thatcher marked yesterday's occasion by having lunch at Green's Restaurant and Oyster Bar in London's exclusive St James's district with her son Mark and his wife.

Baroness Thatcher celebrated her 87th birthday on Saturday. Credit: Stefan Rousseau/PA Wire/Press Association Images

Writing on Twitter, Mr Romney - the Republican challenger engaged in a close fight with Democrat Barack Obama for the White House in next month's election - said: "The US is blessed with courageous friends.

"Happy birthday to the Iron Lady, Margaret Thatcher - a tower of strength in the cause of liberty."