Petrol Station Blues

[Mucus]

When I fill up my MGBGT with petrol, the trigger on the fuel nozzle has to be squeezed slowly otherwise it clicks as if it has overfilled and cuts the flow. Is there a special part that goes into the filler pipe that stops this from happening or is it a case of modern pump nozzles for modern cars? The upside is I spend so long filling up, everybody else at the petrol station thinks I'm loaded!

[Mucus]

It doesn't matter what pump I use, they all seem to do it.

[Mucus]

The filler pipe to the tank doesn't have any kinks or blockages, as Wildoliver says, "It's just a big hole". I wondered if there was a standard device fitted to modern cars to stop this happening.