The workers’ body was joined by Sir Ronald Cohen, known as a pioneer of British venture capital for his founding role at Apax Partners, who gave Gordon Brown’s embattled government £250,000.
The hefty donations brought Labour’s fundraising total to £3.7m at the end of April, according to the Electoral Commission. David Cameron’s Tories were not far ahead with £4.3m.
So far the general election campaign has seen hedge fund managers, private equity players and senior investment bankers pour cash into the Conservative party’s coffers.
The latest numbers show that Neil Ostrer, the secretive millionaire behind Marathon Asset Management, gave Cameron’s team £50,000. Wealth management company Berkeley Burke donated £20,000 while Robert Fleming, a member of the famous banking family, handed over £25,000.
Other high profile City figures to give the Conservatives money earlier in the campaign include former JPMorgan Cazenove boss Naguib Kheraj and Lazard International chairman Ken Costa.