Energy privateers felt the heat as two top-level bodies launched investigations today into claims by a whistleblower that they have been fixing gas prices.
The Financial Services Authority and energy regulator Ofgem are both looking into the claims by Seth Freedman, who worked at ICIS Heren, a company responsible for setting so-called benchmark prices.
He raised the alarm that Britain's £300 billion wholesale gas market has been "regularly" manipulated by some of the big energy companies after identifying what he believed to be attempts to distort prices.
Energy Secretary Ed Davey told the Commons that it was too early to indicate what impact consumers had suffered if the claims were true.
Mr Freedman told BBC News: "Having spoken to traders and other market participants, it seems like manipulation is rife in the gas market.
"Our claims are centring on a particular incident that occurred on a key date in the gas calendar, September 28, in which it seems that people were trying to manipulate our assessment of the market and that is what is being investigated now."
The big six energy companies all released statements denying any involvement.
CPB general secretary Rob Griffiths - candidate in the Cardiff South & Penarth parliamentary by-election on Thursday - said: "This is further proof that we need to take the gas and electricity industries out of the hands of the robbing, lying and cheating fat cats.
"Their profiteering appears to know no bounds and it is high time the Labour leadership reflected public opinion and demanded the return of the energy sector to public ownership."