But the more people look at the scheme, the fewer friends it has.

ECONOMIST: London Underground

But environmental group Friends of the Earth said the scheme, which counts towards the government's 2020 renewable energy targets set by the EU, did not go far enough.

BBC: Renewable heating systems: Household grants available

Ruderman ran his Ponzi scheme from 2003 through 2009, targeting family members and close friends.

FORBES: Tobey Maguire, Billionaire Alec Gores Being Sued For Poker Winnings From Jailed Ponzi Schemer