Last of the Summer Wine - Season 21 Episode 7
From Here To Paternity

Compo recieves a personal letter after all these years. When Clegg and Truly open it they discover Compos biggest secret: he has a son. The son, Tom, wrote to Compo, because after all the years of separation he hoped he and his father could get together. When Tom arrives in town its up for the pair of them to give him the shocking news.