How will the vote change the colour of the capital?
When the dust settles after the elections in London's 32 boroughs, it may tell us something significant about how the capital is changing.
Are Labour voters shifting outwards into the suburbs, while a Conservative-leaning property and professional class fills out the centre?
On the one hand this could be the election which cements Hammersmith and Fulham for the Conservatives - a permanent Tory extension to that double-fronted Westminster-Kensington townhouse painted in the simple colours of low tax and streamlined services.
On the other, it seems more likely than not it will give Labour the keys to Croydon town hall, perhaps as the historic divide between the Labour- solid north and the leafy Tory south of the borough becomes blurred somewhat by the demographic changes wrought by house prices and population growth.
In London as a whole, Labour start from a high base, having done well the last time these battles were fought on the same day that Labour relinquished national authority in the 2010 general election.
They control 15 councils and are eager to lower expectations, but it will be pretty disappointing for them if as well as Croydon they don't make other gains.
They want to win Redbridge, currently run by a local Tory-led coalition; Merton where they have been running a minority administration for the last four years; Harrow where an acrimonious split within the ruling Labour group has allowed the Tories to take over; and finally Tower Hamlets, where the independent mayor Lutfur Rahman - a splinter from Labour four years ago - is seeking a second term.
Then there's Barnet, arguably the best indicator either of something decent stirring for Labour or the limit of their appeal.
Under the Conservatives, Barnet has achieved municipal notoriety by first pursuing an 'Easyjet' model of basic service provision with the offer of add-ons at a price, and then reinventing this as an initiative branded One Barnet outsourcing what critics argue is 70% of services by sector but which the council says amounts to 8% of the budget.
Read the offerings of the unforgiving local bloggers and recall the past protests against this privatisation process, especially the feelings generated over parking, and you might think it entirely possible that Labour could win the 11 seats necessary to take control.
Yet, attachments form and incumbents are hard to budge. Are the services now provided notably inferior, the privatised offer so different, that it will alienate voters?
This particular Barnet formula is just one of 32 different responses there have been in the capital to a time of severe financial challenge. Between 2010 and 2015 London councils will have lost a third of their government money.
Some experts say hardship has been the midwife to creativity and innovation. Partnerships with other councils, the private sector, charities and third sector organisations have become commonplace.
Services have not collapsed, though the effect on libraries, sports centres and advice services in particular hasn't gone unnoticed. Perhaps, the secret in general has been trying to ensure that for the majority of people the most visible services have been maintained. For the more needy, this may not have been the case.
Council tax has been frozen or cut across London. But it's not the case that there has been complete uniformity or de-politicisation - that's clear from a look at boroughs' contrasting approaches to affordable housing supply.
And, will voters use these elections to make their views known about the spare room subsidy, aka the bedroom tax, or other benefit changes?
As the Local Government Association has just warned, we are only halfway through the Coalition's programme of cuts, and councils may be close to the "end of the road" in terms of exhausting relatively pain-free cost-cutting options.
At this round of local elections, how much will voters make either choice on the basis of who best they trust to deal fairly with the strains ahead?
In terms of political fortunes, significant signals are likely be sent to both the Liberal Democrats and UKIP in the capital. Half a decade ago the Lib Dems were a substantial force in well over half a dozen London councils.
Those advances may have been gains initially based on protest, but in some areas they dug in, proved themselves, and hung on to their town hall influence. Yet unpopular in coalition government, it will be hard now for them to retain Kingston and be left with any more than, probably, Sutton.
The searching question for UKIP is whether the capital's voters will show themselves more inclined than in the past to embrace political extremes. Can the party overcome the usual obstacles of demography and diversity?
UKIP's performance in London over the last decade has consistently fallen behind their showing elsewhere in England. And while in 2004 - with the charge of Robert Kilroy-Silk - they picked up two seats on the London Assembly, that was by proportional representation not the first-past-the-post system which operates for London's councils.
Nevertheless it seems reasonable to expect UKIP to pick up a number of council seats, mainly in the suburbs and predominantly in those in the east - and they could play a more influential role indirectly by splitting the vote in other areas.
Recent polling suggests though that while they may secure at least 20% of the vote in the European parliamentary elections -and add to their current single MEP in London - they may remain fourth behind the Lib Dems in the borough elections, although get into double-figures percentage-wise, and - on present indicators - go well ahead of the Greens.