This is for anyone who wants to be a bit more active on election night rather than just listening to the pundits. You can be your own expert, and track for yourself what's going on. It is resolutely low-tech, but has been proved to be quite fun and copes well when results are coming in fast.
All you need to do is:
The sheets also keep track of marginal seats, including some high-profile seats which might have a surprise result.
The first three sheets are the index sheets. These contain all 632 constituencies (excluding Northern Ireland) in alphabetical order. Next to each seat is the winning party in 2015, the predicted winning party today, and the predicted winning majority in this seat (in per cent).
For instance, an interesting seat is the Bishop Auckland seat in the first column
showing that Blackpool South is predicted to be a Conservative gain with a predicted majority of around 0%. Using the predicted winner and majority, we will index this seat as a "Con-0" seat. That is the Conservatives are predicted to win the seat with a 0% majority.
The next three sheets, the party sheets, show the predicted wins for each party, in order of predicted majority. For instance on the Conservative sheet (page 5), we can look for Bishop Auckland as a "Con-0" seat and find it at as the second entry of the first column:
This confirms to us that Blackpool South was held by Labour in 20105 and we know that the Conservatives is predicted to win it because we are on the Conservative sheet. It also tells us the crucial number "70", which would be the Conservative parliamentary majority (CMaj) if the Conservatives won Blackpool South (and all easier seats), but failed to win any closer Conservative seats.
In other words, if the Conservatives win Blackpool South their majority should be at least 70, but if they lose it, their majority should be less than 70 or there will be a hung parliament. As seats are declared and marked on the party sheets, the colours will indicate how high (or low) the Conservative tide is flowing. If the Conservatives win most of the seats in the first column of their sheet, then they will have a majority in parliament.
Conversely if Labour are able to win most of the first column and about half the seats in the second column of the Conservative sheet, then Jeremy Corbyn will have gained outright victory.
The last sheet (page 7) shows marginal seats, which have a predicted majority of less than 8%. The other sheets show the big picture of which parties are doing better or worse than predicted, but this sheet gives some finer detail.