Father's Day - Rare 1979 drama starring Nicholas Lyndhurst (Only Fools and Horses; Frasier)

Drama set in the 1950s. Teenager Philip (played by a young Nicholas Lyndhurst) has a day out with his father, whom he has not seen since he was two years old. His mother is not keen to hand her son over to the man who deserted them. This rare programme has not been seen since first broadcast 45 years ago. Nicholas is currently co-starring in the revived series of Frasier.
NB: Short audio edit for copyright reasons at around 33 minutes in,