I was showing London to a friend and we spotted this beautiful bird. I googled the picture and it said Great blue heron. To make sure I searched the difference between the Gray heron and the Great blue heron. I am convinced that this one is a Great Blue Heron, but I will leave the pros to tell me.
Looks like a young Grey Heron I think Blues are very rare visitors
It's a juvenile Grey Heron. Along with young starlings it is a bird we get questions about several times a year. With regards to the Great Blue there are only 3 British records, the last being 2007 on the Isle of Scily. Google id's need to be cross checked as it has a very strong North American bias. I prefer to use Obsidentify as it is a European database but it's still not perfect but can point in the right direction for further research
Cin J