Margaret Thatcher is due to return home this morning after a health scare saw her admitted to hospital last night.

The 80-year-old former Conservative prime minister was admitted to the Chelsea and Westminster hospital in London after feeling faint during a visit to the hairdressers.

But a spokesman for the hospital said it was merely a precautionary measure, and Lady Thatcher would be well enough to leave today.

The so-called Iron Lady, who was prime minister from 1979 to 1990 and now sits in the House of Lords, has suffered from a series of small strokes in recent years.

“She is fine. She has had a comfortable night and she will be assessed by doctors this morning,” hospital spokesman Mark Purcell told reporters this morning.

“She was kept in overnight as a precautionary measure and doctors will look at her to decide whether she can go home later today.”

New Conservative leader David Cameron said he was sorry to hear that Lady Thatcher was ill, and added: “I wish her a full and speedy recovery.”

Lady Thatcher has been told by doctors to take it easy in the past few years, although she defied instructions not to speak in public when she celebrated her 80th birthday in October.

About 650 people were invited to the party, including her successor as Conservative prime minister, John Major, former party leader Michael Howard, and Tony Blair.

Mr Cameron was not invited – the only Tory leadership candidates that did attend were right-wingers David Davis and Liam Fox.