UK Telephone validation check

Hey. im trying to validate UK landlord (and potentually mobile) numbers users try and list on my Application. I have been reading up on the  National Telephone Numbering Plan from the very useful <a href="http://en.wikipedia.org/wiki/Telephone_numbers_in_the_United_Kingdom">wiki entry</a> and was wondering if anyone knew of a custom validation method of validating either landlords or mobile numbers or both, in the UK only. thanks Si
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