You will need a licence to deal in and collect scrap metal. You will need a licence from the licensing authority where your scrap metal business premises is located, this is usually your local council. If you do not have a permanent premises, you will need to register with the licensing authority where you normally live. If you do not know who that is, find out at Gov.UK, find your local council
To get a licence, select the authority that applies to you:
Fees can be found within the related documents section.