India has condoled with Britain on the death of its former Premier Margaret Thatcher, with Prime Minister Manmohan Singh expressing his "deepest sadness" over her demise.

"People of India join me in sending our sincerest condolences to the Thatcher family, the government and people of the United Kingdom," the Prime Minister said in his condolence message.

Describing the "Iron Lady" of Britain as a "transformative figure", Singh said that under her administration the United Kingdom "registered important progress" in national and international arenas.

Thatcher, the first women Prime Minister of Britain, died of a stroke at the Ritz Hotel in London Monday.