Planning and business rates

[hardlylikely]

Hi guys, wonder if anyone can offer some planning advice:

I am thinking of building an extension to my industrial unit at work. The extension wouldnt be heated or have power in it and would be open to one elevation for lorry access, so really a large lean-to against the main building.

Can anyone advise:

1) what planning consent would I need?
2) is it liable for business rates?
3) Would it be subject to the same fire regualtions (intumescent paint on steels)?

Many thanks in advance

[hardlylikely]

Thank you both for the replies. As I suspected its not clearcut, I think i will open a dialogue with my planning officer at the council and see if they are minded to support such an application.
I really need to understand the likely business rate costs, i could do with finding out if there is a published table outlining the potential discounts against the standard rateable value. hopefully they will offer guidance here too.