Your energy bills: Who is actually charging what?

While Ed Miliband and the energy companies square up to each other, it's worth knowing how your expensive energy bills are actually made up.

Breakdowns vary a little from company to company, but this detail from Scottish Power gives a flavour.

On a £100 pound average energy bill:

• £50 goes to the cost of energy, the wholesale cost that the energy companies themselves don't control

• £21 goes to getting the power to your home - these costs, for example the National Grid, are regulated by the authorities and have been increasing significantly

• £15 goes on green levies, decided by the Government to go to projects like installing insulation for vulnerable customers - this also includes the VAT

• £10 goes on costs of customer service, metering, call centres and the like

• £4 goes on profit - and it is out of that amount that cash to spend on new power stations and infrastructure must come

• Read: Could Labour's price freeze be blocked in the courts?