Is there any legal requirement to advise utility providers, mobile phone / broadband providers, insurance companies etc. that you are BR if you do not owe them any money?
If you are asked the specific question, then yes you do have to tell them.
It's worth checking the T&C for anyone you are considering using. I do know that British Gas have a habit of checking the Insolvency Register, and don't forget that the vast majority of companies will credit check you.
Buckle your seat belt Dorothy, 'cos Kansas is going bye bye.