Being new in the UK, it's hard to grasp right away what the regional dialing codes mean and easy to lose money out of lack of understanding, especially with rogue companies out to take advantage of everyone. I'll try to cover the most common and most costly of them. 070 numbers: There seems to be little bit of trickery going on with some of these, and very costly. Site member/moderator GrahamE states on Well House Consultants that: "You can register one of these numbers at no cost to yourself and ask people to call you on it, and the calls will be put through to you. The intent is that they are "personal numbers" that you can divert from one phone to another, but many callers are unaware of how much it costs to call them and unless you're going to pre-alert people when you hand out your number, you're likely to have some very upset contacts." If you are asked to phone or fax a number with the prefix 070, you should be careful. You can incur a per minute charge of up to 50p/minute. And the call receiver, has gotten this service at little or no cost themself. While it is against the law for companies offering these personal redirected numbers to give commission from the calls to the person who hired the service, it may be possible that it's still happening, ads have been seen that indicate that some might be. It's easy to confuse because mobile numbers begin with 07. 0870, 0844, and 0871 numbers: GrahamE states on Well House Consultants (http://www.wellho.net/archives/2005/02/index.html#a000201) that: "Numbers that start with 0870 are known as non-geographic telephone numbers and they're ones you might want to be careful of too. It depends on who your phone company is, but I don't think that many of the good rates that you get to a normal geographic number extend to them. I've been given a link to a site that lists alternatives to 0870 numbers and I pass it on in case it might be useful to you." http://www.saynoto0870.com/company_search.php 09 numbers: These numbers are most always pay service numbers such as prize claim lines, psychic hotlines, and the like. Beware the prize award flyers you get out of magazines and newspapers, you might win a £10 prize but spend more than that on the phone call to claim it! Telesales: It seems that in addition to what numbers we're aware of dialling, you have to be careful of being connected to a premium rate number by mistake. Some callers might suggest you key a number to find out what prize you've one, while not informing you the cost of keying that number as it will connect you to a premium number. Unwanted Sales Calls: Can be cut down by registering here: http://www.tpsonline.org.uk/tps/what/. You can further prevent these from not giving your number to the sales agents in the town centres giving away holidays and such. I've found the most persistent callers are the window replacement and kitchen fitting firms. Blocking Premium Rate Numbers: Dial 150 on your BT landline to prevent calls to these numbers, you must go through an automated phone menu system to do this. International numbers: Beware of international numbers being rewritten to appear as though they are not international. International numbers (from the UK) always begin with 00 (ie. USA = 001) If you see a dash in between the written number as in 0-01.. it's still an international number! For a more detailed guide to the cost of phone calls, please see Guide to charge rates, note Section 2. http://www.serviceview.bt.com/list/current/docs/maintoc.htm%20target= 0845 numbers are safe, these are Lo-call numbers, and charged at a local rate. 0800 numbers are used the same way as toll free numbers in the USA.