fax numbers

[Richardmac]

How an I obtain fax numbers of UK businesses?

[cupra]

If you are looking for a free list, I doubt you'll find an up to date one - you really need to go to someone like:
Kompass - http://www.kompass.co.uk - you can order reports on business type/locations etc..
Kelly Search - http://www.kellysearch.com/ - similar but less detailed information
Applegate - http://www.applegate.co.uk - more of an industrial bias
If you are planning a marketing 'fax-shot', make sure you look at the respective codes of practice or Oftel can get upset!