Looks like a dove to me. Difficult to guess the age. Definitely not a baby, there's no yellow fluff. Check online for species that occur in your country and compare him to the images. Do you suspect something might be wrong with him?
Thanks so much for replying... it's quite small, hard to show on a picture. I googled UK Doves/pigeons and it looks quite like a mourning dove.... so beautiful.
As for injury... yes, underneath the shoulder is totally damaged rendering it flightless. I feared that a cat might play around with it if I didn't bring it home.
He will need antibiotics if a cat got hold of him, cat saliva is deadly for birds. Unfortunately you will need a prescription in your country to get some. You don't have any amoxycillin based antibiotics like Betamox, Synulox or Clavmet perhaps?