What is the difference between a Key seat and a Marginal seat?
Marginal seats are defined as anything with a margin of under 6 per cent. Seats between 6 per cent and 12 per cent are defined as Safe, and seats with a margin above 12 per cent are defined as Very Safe. That means that at every election, all the seats under 6 per cent on both sides of the electoral pendulum are defined as Marginal. However, thanks to opinion polls, we have a general idea which way the swing is going to go at an election. That is why we separately define seats as being Key. Key seats are defined by analysis of the likely course of the election and by newsworthiness. Marginal seats are simply defined by their swing to lose. Even Very Safe seats can become Key seats. A strong independent challenge in a Safe seat may be of interest even if on paper the seat is safe.
