I'm completely guessing here, but isn't there some sort of law or regulation that the police are required to give you truthful information regarding your right to legal representation?

As such, and while this wouldn't take away from the stupidity of not getting a solicitor involved, maybe he asked the question not because he wanted an answer, but because he thought there was a chance the policeman might say "no, you don't need one of those" and create a problem for the prosecution?