'Going Straight' is often thought of as a failed sequel to 'Porridge.' However, it would help to think of the show as an epilogue to 'Porridge.' If both shows were called 'Fletcher' then I very much doubt that any distinction would be made between the two.
By the time the show was written Ian La Frenais, Dick Clement and Ronnie Barker had the mind of Fletcher down to a tee. This in itself made the series superb - with some of the finest writing and acting to adorn our T.V. screens. But there is a more important point to 'Going Straight.' Although 'Porridge' tried to relate the daily grind of prison life it was, by it's very nature, a comedy programme. Fletcher's spirit, intelligence, humour and status inside 'Slade' almost made you want to commit a felony and go and join him. However, once outside he became a 'nobody.' The writers cleverly showed that outside a prison Fletcher was on life's bottom rung - on course for a life of menial work, low status and even lower pay. Fletcher finds himself very frustrated at the lack of opportunities for ex-cons, especially at his age, and this comes through in the series quite strongly. Personally, I admired him in 'Porridge' and pitied him in 'Going Straight.' In 'Porridge' it was often referred to that the system can't be beaten. 'Going Straight' showed that even after having served time for crimes the system still controls your destiny. A lesson for us all.