@Kara198
Peston is somewhat rubbing people's noses in it but unfortunately he does have a point.
Back in May the main reason why People's Energy (PE) was the cheapest deal is that unlike the bigger competitors PE did not put in places hedges (bit like insurance) on energy prices going higher. Maybe because they couldn't afford to or choose not to in order to keep their prices lower and capture you as a customer.
This is especially important on a fixed price tariff for example if they agree to sell to you at say £100 (pls other costs and profit), they should then hedge this at £100. If they don't hedge and future prices go to £150 they still sell to you at £100 but go bust but if future prices drop to say £50 they still sell to you at £100 and get rich.
The problem with People's Energy is now that British Gas have taken on the customers, BG will pay more for the energy than it can charge to these ex PE customers. Taking on PE customers will cost BG about £200 million.
BG will then look to recover this £200 million by charging where it can from its existing customers more.
To summarise you got a cheap deal back in May because PE (and other small suppliers) was flying by the seat of their pants. That eventually caught up with PE and they went bust. The cost of clearing this particular mess up is then paid by British Gas customers who maybe paid more than you did in May this year but did so because they wanted the security of a larger and safer supplier.
Sadly these BG customers will now even have to pay more to continue the supply to PE customers .