UK telephone prefix location lookup
 

Hello. The reason I ask this question here rather than spend some time on google is:::
1. People here will know the answer.
2. People here will know which sites are more useful or have better user experience.

What I need is a web site that I can use to look up 'UK' calling prefixes. "UK" is in quotes because I also want to look up Crown Dependencies prefixes and they are regulated by UK agencies even if they are not a part of the UK or EU.
Crown Dependencies include The Isle of Man, Guernsey, and Jersey. Perhaps there are relevant others.

Why I ask in International is that many of these prefixes are used with International SIM cards.

thanks

I used this site. Can't vouch for it's accuracy, though: UK Area Codes - search and browse area code listings

Here is the info I was really looking for.
 

Here is the info I was really looking for.

There are plenty more UK mainland mobile exchanges that are on par with or more expensive than those in the IoM, Guernsey and Jersey. Mundio and Telna are just a couple of examples.

I wonder if the regulated mobile termination rates do apply for those MVNOs. All the publications about British termination rates only mention O2, EE (formerly known as T-Mobile and Orange), Vodafone and 3, for which termination rates are set to fall dramatically to mere £0.0069/min next month (Ofcom | Regulated prices - end of page).
For a complete list of assigned area codes and other number ranges see http://www.ofcom.org.uk/static/numbering/s7.xls
What I also find interesting is the fact, that many carriers charge calls to British mobile numbers depending on their prefixes despite the UK has had MNP for a decade or so. I heard of people who buy Vodafone SIM cards just to export the number to another operator, whose native numbers are often more expensive to call, in order to be reachable at lower costs for callers.

I've been using these two for years:

CodeLook

UK Telephone Code Locator - Telephone Codes, STD Codes

The rates for mainstream MVNOs will be the same as the network they inhabit, as they'll be using the same range of prefixes. For example a giffgaff SIM will originally have a number allocated to O2, and an Ovivo one a number allocated to Vodafone

Some of the MVNOs have their own number series, for example Lyca or Turuphone, and this does seem a bit more expensive from one or two retail providers with

There are allocations to companies which don't seem to have traded as mobile networks, or they might have SIMs in some ranges and other products in others. Some are offering VoIP over wifi and have a mobile incoming number rather than a landline. Mind you conversely some VoIP providers are operating small MVNOs, mainly via a partner on 3, and some of those offer landline numbers tied to the SIM (and charge the user incoming calls)

Some number series get let out to other providers who might offer callthrough access using the margin on termination rates - they collect the incoming rate and their gateway lets callers reach international destinations.

Unsurprisingly the networks don't like this too much, and keep themselves up to date with new series springing up, and then exclude them from contract inclusive minute bundles, and maybe increase the rate charged to payg users.

Calls to the bona fide Guernsey Jersey and Isle of Man networks, plus others such as Truphone and other roaming SIMs, vary in their billed treatment by UK main networks. Some include, some exclude and charge something rather high like 40 or 50 pence a minute. This might imply higher termination rates, but certainly not that high. Personally I feel that a network advertising that it has good rates to European mobiles ought to be taken to task about this.

I see bill-shocked people on other forums complaining about these bundle exclusions from time to time, especially that poorly trained customer services at their network come up with some odd explanations, such as falsely alleging callthrough use. Thus on one forum someone was convinced that Lycamobile is based in Jersey, which it is not.

I'm thinking the people you are referring to porting the numbers may have been mistaken in their hopes, as usually a ported number will assume the billing characteristics of the actual network of the SIM, rather than the ported in number.

So if my very old (but free!) O2 contract with only O2 and landline minutes was used to call a number ported from O2 to Vodafone I would be charged.

But there will occasionally be people suggesting that someone might try porting an Orange or O2 number to a Lyca SIM to get T-mobile to include it. I don't know if it definitely works. Some people on forums declare something as fact when it's only a guess, then might keep quiet ...

Whether the island networks are also reducing their wholesale termination rates, though at a slower speed than EU countries, I don't know. But it seems to me if some of them can offer 9 pence a minute retail rates to their neighbouring networks, which Airtel-Vodafone does, they are unlikely to do so at a loss.

What the small callthrough providers on odd prefixes do with their termination rates, and how they bill and receive their income, and what Ofcom does to control them, I really don't know. Considering that the main networks are probably in dispute with them, and presumably refusing to pay in full, I don't know how they keep springing up.

As for the look-up asked about to begin with, my favourite is the Magsys Codelook that NFH already posted

Oops, sorry this is a bit long.

Expanding on NFH's post:

The Magenta Systems CodeLook CodeLook is an extremely effective way of checking on who operates a UK number range - and how calls to numbers within the range are tariffed.

Of course - this does not take into account ported numbers - but as a quick and easy way of checking numbers (that is nearly always correct) it is brilliant.