David Cameron said it was "about time" as he hailed the start of an £8 billion redevelopment of Battersea Power Station.
The Prime Minister visited the central London site - which has been lying unused since 1983 - with his Malaysian counterpart Datuk Seri Najib Razak.
Speaking with Mr Najib, the premier said: "This is a great day. It has been a long time to get the Battersea Power Station development going.
"It stopped producing power 30 years ago and it has taken this long to get off the ground. It needed your help".
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But Tower Hill Underground station just a few hundred yards away will be shut because of engineering work on the District Line.