Yes, that’s Margaret Thatcher.
The photo is from 1975 when there was a referendum on whether the UK should stay in the European Community. Margaret Thatcher was the leader of the Conservative Party back then. Given what she wears, I don’t think I need to point out her position on Europe. 67% of voters wanted to remain in the European Community (which later became the European Union).
It seems like Britain’s days in the EU are numbered. It is shocking to see how little the current British Prime Minister understands of Europe (and the same applies to most of the British media). Whenever I hear David Cameron talk about the EU, I want to mail him a copy of “The European Union for Dummies”.