Miss Courtney wants a celebrity to open the school fete. Max says he knows the comedy actor Arthur Mullard personally and Miss Courtney asks Max if Mr Mullard could open the fete for them.
Max doesn't really know Arthur Mullard, as he was just bragging.
After Max and Giovanni are in the Pub when Sid drops in for a pint. Max asks him to ring Miss Courtney, and apologise to her and say that he can't open the fete after all.
When Miss Courtney says there will be a small cash payment, Sid thanks her and will see her at the fete.
A man sitting at the bar looks exactly like Arthur Mullard and Max tells him so, and it turns out that it really is Arthur Mullard, so Max asks him if he would open the fete. He agrees and Max is out of trouble.