Mobile phone numbers
07720 numbers are for mobile phones in the United Kingdom.
All UK 07 numbers are for mobiles, pagers and personal numbering.
Which network is 07720?
07720 numbers are allocated to O2.
It is no longer possible to tell the operator of a UK mobile phone from its number alone, as customers are free to take their number with them when they change networks. The 07720 prefix is not a reliable indicator of which network a phone is currently connected to, only which network issued it originally.
Formatting an 07720 number
There is no set format for UK mobile phone numbers, but the commonest format is: 07720 xxxxxx
For international callers, use: +44 7720 xxxxxx