How do I find out how my gas and electric suppliers are?

Hi, I don't know who my gas and electric companies are. I remember in my last flat I rang some company and they could tell me my suppliers, but I can't remember who they were. Strangely no one else seems to have heard of them.

National something I think
Answers:
i thought i was with british gas but when i phoned them they said i wasnt but they gave me phone number to phone to find out sorry i dont have the number but phone british gas they should give you the number
don't you get bills from them.
One thing would be to wait until you receive your bill. Another would be to call your landlord and ask who supplies it(if you are renting). Also ask the other tennants who supplies theirs, I'm sur they have gotten bills before...
In the UK.

You can contact any gas and electric supplier and have them supply your fuel. You don't have to stick to any one supplier and you can actually shop around for better deals.

They don't have to change the pipes or anything it's all sorted out between the companies.

If you owe anyone money then they should send bills to your location and you can find out that way.
check if there are any bills left lying around by the previous tenants
call the letting agency or contact the landlord/lady
look at your bills, it will have their name at the top