Middle-aged bus driver Stan Butler lives with his mum,sister Olive and her grumpy husband Arthur. He and aging Lothario conductor Jack are constantly battling miserable inspector Blakey and when Blakey closes the canteen after Stan has been eating in the bus cabin,industrial action is called for. Stan lies in front of the bus Blakey is driving and attracts the attention of a news crew.
A new conductor turns out to be a conductress, Iris,whom Stan dates. Despite being middle-aged he does not want his family to know and says he is on a late shift whilst taking Iris to the pub,where Arthur sees them. Arthur and Stan's mum also foil Stan's efforts after he has brought Iris home though he eventually makes up with her.
To Stan's horror Olive gets a job as a bus conductress but she gets sick from the diesel fumes as well as getting stuck in the doors. It is down to Stan to think up an ingenious plan to get Olive off the buses - like saying that she is pregnant.
Stan is not feeling well as he is suffering from stomach aches. Arthur reckons it's because he eats too many chips and other fried foods and suggests he go on a diet. At the same time the depot are giving the staff medicals and those deemed unfit will be put on menial duties. Stan goes on the diet and passes the medical though finds it might have been better if he had failed it.
When a vacancy arises for an inspector the crew-men are not keen to apply,fearing that they will end up like Blakey. But needs must in the Butler household as Mum needs a new coat and Stan takes the vacancy. However he soon realises that he is better off doing his old job and is happy to return to the ranks.
The bus staff are given some say in the running of their canteen and Stan is put in charge as manager. He employs Mrs. Sharma as a cook but she can only make Indian dishes and so he replaces her with Olive. This is an even worse executive decision as Olive is a terrible cook and ultimately Stan is reduced to buying fish and chips from the local takeaway.
Following an argument over the use of the staff darts board Stan and Jack are challenged to a match by his old flame Iris and her friend. Stan tries to practice but drops his darts into Olive's stew and has trouble adjusting to his new set, ultimately - thanks also to Iris's wiles - losing the match. He is replaced on the team by his Mum,who proves to be an excellent player.