The country dialling code for United Kingdom is +44or 0044 (they're both identical).
If you want to make a call to United Kingdom from abroad, you have to dial the following country code +44 (or 0044) followed by the national telephone number.
National telephone number: 0800 123 4567 (for local calls)
International telephone number: +44 800 123 4567 (for calling from abroad to United Kingdom)
Capital : London
Population : 64 800 000 Inhabitants
Time : 2019-02-20 11:01
Time zone : Europe/London