Roy Clarke needed to fill a hole left behind with the death of Bill Owen which meant the death of Compo in the series.
Clarke turned to Bill's real life son, Tom Owen who appears as his long lost son also called Tom.
As Clegg discovers there were a few things about Compo he did not know. Although Compo was briefly married, it seems he might had spread his oats here and there leading to correspondence with someone who thought Compo might be his dad.
It is left to Clegg to tell this newcomer Tom that he will never get to meet his real dad. As the crowd gather in the pub they recognise straight away that Tom looks like his dad.
I guess some people never realised that Compo was short for compensation, something the character made money out of claiming. Tom in his first appearance claims to get whiplash for some sudden braking he did as Howard gets in his way. Tom later tries to scam Howard again for some damage to a coach.
There is a melancholy edge to these episodes as the characters still try to get to terms over the death of Compo.
However Tom is a down on his luck scammer and I guess it is a reason why his character never took off. Tom was later relegated to doing errands with Smiler for Auntie Wainwright.