There are no free 'reverse lookup' telephone directories for private individuals in the UK, as far as I am aware. A company called 192.com supply a range of CDs that allow you to do this, but those with reverse lookup facilities are not cheap - £150+ from memory.
You could always try typing the phone number into Google (with and without a space between the area code and the actual number) - it is surprising how often it throws up a result.
But Jakedaw's answer has to be the quickest and easiest :)
Thanks for the postings, now have another source for sending the letter, cant ring the person as the number was given by a 3rd party......the letter i need to send is a letter of complaint re a football team/manager/coach
Now going via the Football Association with the complaint
This thread is now locked and can not be replied to.