In the UK, mobile handsets are subsidised by the operators so, in order to prevent handsets being connected to a rival mobile network, it is common practice to 'lock' them.
It's also typical for the network operators to offer their loyal customers a new handset about every 12 months. So many parents have a draw full of unused handsets because their off-spring want to use a handset connected to a different network.
It's not actually illegal to 'unlock' a handset - although it is generally frowned upon by the operators themselves. Most UK High Streets have at least one shop offering to unlock handsets for around £20. It is, of course, illegal to tamper with a handset's unique IMEI number.
The INQ went onto the site unlockthatmobile.co.uk and followed the instructions. It involves placing a call to a premium rate telephone number at £1.50 per minute.
We estimated the total call took around five minutes so that's £7.50. Not too bad and more convenient than handing over the handset to a high street retailer.
It might be worth checking that your exact Nokia model is supported before making the call.
That's not to say that unlocking a handset isn't dangerous. Just ask eighteen-year-old Philip Croker.
This Cheltenham based lad asked his Dad how to unlock a Samsung phone. His Dad realised it was stolen, shopped his son and now the boy is doing three years behind bars. µ
L'INQ
Unlock.com
With regards to the above, I tried 
today to obtain a unblocking code from the above named firm,.
All I got was a £5.00 debit on my phone. and no code.
There e-mail address is invalid, and only a premium rate phone number to contact. I will send them a letter , but I dont hold out much hope of my money back. Or any code.
Re
Check allwhois.com for the doman name registration details. nokiaunlock.org.uk is registered to 'Rick' but as a none trading site(!) so no further details are available. It's sister site 'www.cellular-unlocking.co.uk' has the letter 'a' in all the registration detail lines so untraceable. Shame on fasthosts.co.uk which hosts both for allowing this to happen, and shame on The Inquirer for promoting criminal activity.
Tried this premium number and conned me out of 9minutes and 46 seconds of premium rate billing! No email address. Must assume their fax support line is a con too.
May they rot in hell!
My fiance spent over 5 minutes at £1.50 a minute yesterday to this rogue company which gave a code which surprise surprise does not work on my phone!!!
Im so annoyed! This company has no email address to contact if you have problems, or a contact number!!!! another surprise!
A fax to the company yesterday (extra expense)_no reply!!! suprise suprise!!!
Dont waste your money and time!!!!
Reporting this company if there is no response by Monday, though not holding on to much hope of that after finding coments above!!!!!!
I Have been on the phone ages and it does not work what a wast of time and money
I was on the phone ages watching the bill mounting up and I received a code that didn't work and so I thought never mind I will email the company and guess what - they have no email address even though they tell you to email them. 
So it's cost me about £10 for nothing. I might as well have burnt a £10 note. 
I urge people not to be taken in by this too good to be true service or by the Inquirers claim that it does work.