Bell Gas, which had signed up 4,500 mainly business customers from its office at Brent Cross in north London, called in the receivers on 22 March after running up undisclosed debts. Its annual turnover was believed to be approaching pounds 10m.
A week before the management called in the receivers Bell was understood to have received a substantial bill from TransCo, the British Gas pipeline division, for problems with "daily balancing".
Last September suppliers using the TransCo network had to accurately match how much gas they put in the system with demand from their customers. If the sums did not add up at the end of the day they faced punitive charges to buy or offload gas. TransCo confirmed it was owed cash by Bell, though sources denied rumours the bill was for almost pounds 400,000.
Ofgas, the watchdog, said none of Bell's customers had been cut off because the supply base had been taken over by another supply gas company, Quantum.
It also emerged that Quantum, which is a creditor to Bell, bought the customer base just before the receivership.
The oil giant Esso is also thought to be owed money from the collapse, along with Barclays Bank. Bell Gas was created in 1993 after the opening up of the commercial market to competition.