Stephen Smith has decamped to Donington Park services on the M1 to cover the general election campaign after psephologists identified service stations - or rather, the people who regularly use them and live near them - as a group with the power to swing the outcome on 6 May.

This week he has been seeking out tips and predictions on who will win the big race for Downing Street, and getting a lesson in the bookies' language tic tac from horse racing pundit John McCririck.

Broadcast on Tuesday 20 April 2010.