Businessman and leading Labour Party donor Andrew Rosenfeld has died at the age of 52 after a short illness.
Former Jewish Care trustee Mr Rosenfeld was an investor in property and mobile phone company chairman.
Labour leader Ed Miliband said: “I am deeply saddened by the sudden death of my friend, Andrew Rosenfeld. My thoughts are with Juliet and his family.”
Mr Rosenfeld loaned the party £1m when Tony Blair was Prime Minister.
The money was repaid in 2009 and was followed by a reported further £1m donation in 2011.
He became the party's chairman of nations and regions and volunteered to raise support and money around the country.
In the past Mr Rosenfeld had also supported the Conservatives, giving £10,000 to Ken Clarke's party leadership campaign in 2001.
The multi-millionaire returned to Britain around two years ago after spending five years in Switzerland.
He made an estimated £100m through a property investment company, Minerva. He sold the firm in 2006 and moved his family to Geneva.
