I'm writing this on 29 April, 48 hours before polling day, so I have no idea whether Ken Livingstone will beat Boris Johnson or not. That result is immensely important not just for the future of London and for Londoners, but also for Labour as London will be a critical electoral battleground in the next general election.

However, whatever the result, we already know that the electoral process itself has been good for Labour and good for democracy in London. Here's why:

Turnout and voter engagement: turnout is going to be significantly higher than in the previous mayoral election in 2004. Once people start voting again they tend to carry on voting in other elections. This contest has proved that low turnout happens when voters think a race is a foregone conclusion. Presented with a genuine close contest they will engage in the electoral process enthusiastically.

Reaching the parts of London other elections don't reach: this election has had to be fought London-wide. It has been a genuine 32-borough contest with Labour campaigning in every constituency and ever borough, engaging with voters not just in parliamentary marginals but in our own safe seats and opposition heartlands. If you are a Labour voter in Hackney or Newham, or in Chingford or Ruislip, in this contest your vote has really counted, whereas in general elections only the key marginals really matter.

Regenerating the London Labour party: the London-wide campaign has led to the organisational regeneration of branches and CLPs that have not been a priority in general elections, recreating structures where they had atrophied or died.

New (and not so new) activists: volunteers have been attracted to an exciting and close-fought campaign, and CLPs have had an influx of fresh blood and of former activists coming back into activity. Electioneering being both fun and addictive, these people should carry on being active in future campaigns.

Reuniting the London Labour party: hatchets have been buried and deep-running divisions in the London Labour party, dating back not just to Dobson vs Livingstone in 2000 but to Livingstone's coup against Andrew McIntosh in 1981, have been overcome as the entire London party has united around Ken as a candidate. A comradely campaign has seen London Labour remember that the Tories are the real enemy, not each other.

Reminding voters who the Tories really are: Boris Johnson has provided a timely reminder that, whatever the Cameron gloss, they are the same old Tories: crass, bigoted, reactionary, elitist, out-of-touch, and with nothing to say to the people we represent.

Rebuilding the progressive family: the electoral system for mayor, with voters able to express second preferences, has had the positive effect of getting Labour to reach out to Green and Lib Dem voters and remind them that we have more in common than divides us. It has also forced their supporters to make some tough choices about whether they want a progressive Labour mayor or a reactionary Tory one. Those same choices will confront Green and Lib Dem voters in the next general election.

A building block for future elections: even if we lose, canvassing data collected in these elections, along with increased numbers of voters on the electoral register, will be a valuable asset in both the 2010 London borough elections and the next general election.

London Labour, whether it has won or lost, has emerged from these elections in a healthier condition, better organised, more united and cohesive, with its campaigning sharpened up and ready for the battles ahead.

Luke Akehurst is a Labour blogger, at lukeakehurst.blogspot.com