These phone numbers 07700900982 and +447708900982 are not valid

[dimylik]

Interesting case just randomly discovered,
numbers 07700900982 and +447708900982 are not valid, issue is in the second zero, but works for every other number 1 to 9.

"google-libphonenumber": "3.2.33"

const phoneUtil = require('google-libphonenumber').PhoneNumberUtil.getInstance();

phoneUtil.isValidNumberForRegion(phoneUtil.parse('07700900982', 'GB'), 'GB'); //  =>> false
phoneUtil.isValidNumberForRegion(phoneUtil.parse('07701900982', 'GB'), 'GB'); // =>> true, works with any number 1-9, except 0

phoneUtil.isValidNumberForRegion(phoneUtil.parse('+447700900982', 'GB'), 'GB'); // =>> false
phoneUtil.isValidNumberForRegion(phoneUtil.parse('+447701900982', 'GB'), 'GB'); // =>> true, works with any number 1-9, except 0
phoneUtil.isValidNumberForRegion(phoneUtil.parse('+447702900982', 'GB'), 'GB'); // =>> true
phoneUtil.isValidNumberForRegion(phoneUtil.parse('+447703900982', 'GB'), 'GB'); // =>> true
phoneUtil.isValidNumberForRegion(phoneUtil.parse('+447704900982', 'GB'), 'GB'); // =>> true
phoneUtil.isValidNumberForRegion(phoneUtil.parse('+447705900982', 'GB'), 'GB'); // =>> true
phoneUtil.isValidNumberForRegion(phoneUtil.parse('+447706900982', 'GB'), 'GB'); // =>> true
phoneUtil.isValidNumberForRegion(phoneUtil.parse('+447707900982', 'GB'), 'GB'); // =>> true
phoneUtil.isValidNumberForRegion(phoneUtil.parse('+447708900982', 'GB'), 'GB'); // =>> true
phoneUtil.isValidNumberForRegion(phoneUtil.parse('+447709900982', 'GB'), 'GB'); // =>> true

I am not sure why

Looking at the wikipedia: https://en.wikipedia.org/wiki/Telephone_numbers_in_the_United_Kingdom
Mobile number format in the UK: 07x xxxx xxxx
Should not be any limitations for number after 07, as soon as you have 11 digits number.

Also, using different internet resource, I have found, that UK mobile/landline number length might be 10 digits:

• Yes, almost all UK numbers are 11 digits long, including the dialling codes. There are a few areas around the country whose numbers only contain 10 digits, but these are in the minority.
• Mobile numbers: mobile phone numbers in the UK start with "07" and range from 10-11 digits, though a majority are 11 digits.

You might need to update limitation from 11 to 10 characters, up to you.