Even if Ken Livingstone doesn't retake City Hall, 3 May is still likely to be a good night for Labour. The annual pre-election forecast from Plymouth psephologists Colin Rallings and Michael Thrasher, based on local by-election results, suggests that the party could gain as many as 700 seats.
More than a dozen councils look to set to fall into Labour's hands as the electoral pendulum swings from government to opposition. England's second city, Birmingham, is the prime target, but councils from Plymouth in the west to North East Lincolnshire in the east to Carlisle in the north should tumble too.
Unlike last year, Labour is also expected to win a higher national equivalent share of the vote than the Tories. When the seats falling vacant were last contested in 2008, the party won just 24 per cent of the vote. But this year, as the graph below shows, Labour is expected to win 37 per cent, with the Tories down nine to 34 per cent and the Lib Dems down five to 18 per cent.
The one event (aside from the London mayoral election) that could spoil Miliband's evening is the likely triumph of the Scottish National Party in Glasgow. Labour has already lost overall control of the council for the first time in 35 years after a series of resignations and defections, and the SNP, which won five of the city's nine constituencies in last year's Scottish Parliament elections, is on course to win a majority. Should Alex Salmond's party also gain North Lanarkshire, Labour could be left without overall control of a single Scottish council. Such an outcome would confirm the SNP's hegemonic status in Scottish politics and provide it with another platform to make the case for independence.
Miliband will rightly attribute the (likely) defeats in London and Scotland to local factors but that won't stop the press asking, "if Labour can't win in London and Scotland, where can it win?" Miliband's hope is that the party's gains elsewhere will answer that question.