It's relatively new and is a lovely way for utilities companies to side step the rules on cutting people off. They advertise it as an option for people so they have more control over their spending when in reality it has a higher unit charge and is targeted at people who are likely to be financially struggling or close to it.
So what happens is it can just shut off when you haven't paid yet. I work in utilities and I have dealt with literally thousands of homes and these are always in impoverished and working class areas where if the people were to be on a standard policy they would have protections against cut off due to non payment.
This isn't meant as any disrespect to the guy above, I know two sentences about him and that all, just my view of this bullshit.
Yeah I don't think it's new just something you only see in poor areas, it's of course the most expensive way of getting electricity too because they love rubbing a bit of salt in when they screwing the poor.
I remember going to my friends house, the power shut off Saturday night and the post office didn't open until Monday so we were basically camping in his house getting high by candle light.
You'd be better able to tell if your energy is being fucked with if you had a smart meter because you can check your energy usage at any point in the day.
Also you don't have to go near British gas, they don't control the meter anyway.