Many Labour supporters have had their ballot papers and have already voted for their new Leader. And there is a new spring in the step of Andy Burnham. 

A couple of weeks ago, it looked like the former frontrunner might have lost to Jeremy Corbyn, but things are looking up for Burnham.  However it’s going to require some tactical voting by Kendall and Cooper supporters to get him over the line and prevent a Corbyn victory.

Members of the Labour Party make up one of the most politically sophisticated electorates in the world. Many have been involved in elections for years, and they know that this is not a simple first-past-the-post process.

Corbyn might still win on the first ballot, but if he doesn’t, then his chances could die quickly.  This is an eliminating ballot, so there can be two further rounds of counting. As the candidate with the least votes drops out, their second preferences come into play. Corbyn is then in trouble.

If he cannot do it outright, Corbyn has one chance to win.  He must face Yvette Cooper in the final round, because if he faces Burnham, then Burnham will win.

The logic is simple. Cooper’s supporters tend to be modernisers and centrists; whereas Burnham appeals to both the centre of the party and to union and left wing voters who are drawn to him because of his long term battle against NHS privatisation.

If Yvette Cooper is knocked out on the second round, her second preferences go to Andy Burnham and Burnham wins.  But if Cooper beats Burnham in the second round, then his votes are not certain to go to Cooper. Left wing and union votes may go to Corbyn and push Corbyn over the line. That is why Corbyn wants Cooper in the final round. 

This is how it could happen: on the first ballot, Corbyn is first but does not get over 50%. Burnham is second and Cooper third. Liz Kendall will be knocked out. Her second preferences will go to Cooper or Burnham. Corbyn is unlikely to get any of them.

Kendall supporters then have one chance to stop Corbyn.  A second preference for Cooper might just put her ahead of Burnham; Burnham then drops out and Burnham’s second preferences then split for both Cooper and Corbyn, and Corbyn might win.

However, if the Kendall second preferences go to Burnham, and he stays ahead of Cooper, then Cooper drops out and her second preferences, as well as Kendall’s, will go to Burnham. Burnham wins.

The Burnham camp believe that many party members have done the maths and can see that its either Burnham or Corbyn. 

Burnham has received a warm reception from large meetings all over the country.  The momentum seems to be building.

And telephone canvassing by the Burnham camp leads them believe that the ballot papers dropping through hundreds of thousands of letter boxes has had a sobering effect. Voters have been forced to ask themselves who, in 2020, can beat George Osbourne or Boris Johnson? 

Many of the recent opinion polls only counted voters who had decided on their candidate, but for months many party members have been undecided. Increasingly, people are thinking about their second preference as well as their first.

This week’s tiff between Cooper and Burnham reflected this tension.

In practice, ideologically there is little between them. Both are bright, engaging politicians with the capacity to grow in the job and become decent Prime Ministers.  They get on.

This week, Cooper had made a bid for Kendall’s second preference votes by attacking Corbyn.  By contrast, the increasingly confident Burnham is looking beyond the Leadership Election and thinking about how a new Leader can unite the Party and hold onto the many young idealists who have more recently joined. That is why he has refused to attack Corbyn. 

Burnham is not yet in the lead, but he can do the maths, and the maths still says he can win.

Mike O’Brien was a Minister in both the Blair and Brown governments.  He was MP for North Warwickshire from 1992 to 2010.