Click the green flag and maybe don't call the number it can be risky.
It's always a British cell phone number because it always begins with +44 then the 7 right after that means it's a cell phone after the 7 there's apparently never a 0 for a cell phone which is just weird and then after that it's just randomness. There are exactly 900 million combinations. And about 83 million phones in the UK that are active and 11 million that are not active so if you got one of the non-active British phones you wouldn't be able to call them there's about a 1 in 11 chance of getting a British phone that you can actually call. Still I suggest not doing that.