Bertie's Bad Day is a magazine story.
Early one morning, Bertie trundles out of his garage and sets off down the road. Suddenly, as he passes the park, Bertie starts to skid and hits some swings at the edge of the park. Luckily, Bertie isn't hurt and as it's early morning, no-one is around, but the swings are badly damaged. The park-keeper comes running and says he will have to inform the Fat Controller.
The Fat Controller is just getting out of bed when the park-keeper rings and arrives at the scene wearing his pyjamas. Bertie can't explain what caused the skidding and the Fat Controller puts it down to careless driving. Just then, some children arrive and are disappointed to see their swings broken.
As Bertie drives off, he starts skidding againa and the Fat Controller orders him to stop. Wheels wobbling, Bertie reverses carefully back towards the Fat Controller. This time, much to Bertie's relief, the Fat Controller isn't cross. He can see there's a problem with Bertie's tyres and they need changing.
Sure enough, Bertie's tyres are worn out and Bertie goes to his garage to have them replaced. When he sees his old tyres, Bertie has a brainwave. He asks the Fat Controller for some strong ropes and heads back to the park.
Bertie takes the old tyres to the park and the park-keeper hangs them from a tree branch. The tyres made excellent new swings. Now, the children are happy again. Bertie's day hasn't been bad after all, it actually turned out to be a really good one.