Voters in Hove will take to the polls today to elect Brighton and Hove's "kingmaker". But why will the winner of a small by-election have such significance? And what will it mean? Andy Chiles reports.

There are just 11,548 people eligible to vote in Hove's Goldsmid ward, less than a twentieth of Brighton and Hove's population.

Yet today they will be the ones responsible for a decision which will shape the city for the next two years – and quite possibly the longer term future.

Ballots open for a by-election in the area, which stretches around St Ann's Well Gardens, the county cricket ground and Hove station, at 7am.

Two hours after they close at 10pm the outcome will be known and Brighton and Hove City Council could well take a new shape.

The by-election has been sparked by the resignation of Conservative Paul Lainchbury, who came under fire for regularly missing meetings.

Prior to his departure his party had 26 of the council's 54 seats meaning they had enough members, with the regular support of Independent Jayne Bennett, to win key votes.

Crucially this meant they could install an all-Conservative cabinet, led by Mary Mears, to take major decisions.

Mr Lainchbury's departure, in a ward where voting has been closely shared by Conservatives, Labour and Greens in recent years, has thrown up a range of possibilities.

Labour have 13 council seats, the Green Party have 12 and the Liberal Democrats two. If any of them were to win they could combine to install a leader and cabinet of their own, leading to the election winner being dubbed the city's kingmaker.

So the key question is what will happen if each of the parties wins – and could Brighton and Hove be governed by a "rainbow coalition"?

CONSERVATIVE

A Conservative victory would maintain the status quo, with the party taking control of key decisions despite having less than half of the council members.

It would be taken as a seal of approval for the party for their work since they wrestled control from Labour in the 2007 city elections.

They have been attacked by opponents, who labelled them a "do nothing" council, for turning down plans for a major development at Brighton Marina, failing to move other key projects forward and having a perceived lack of direction. Union leaders have criticised them for their handling of pay restructuring within the council.

But the Conservatives maintain they have been quietly making the council more efficient and effective. They have stuck to pledges of low council tax increases by trimming council spending, announcing that they came in £2.4 million under budget in the last financial year.

They have concentrated investment in low key projects, such as refurbishments of London Road and The Lanes car parks and the £950,000 seafront bandstand restoration.

A win would give them another two years to stamp their mark on the city.

They come into the election with their party on the ascendancy nationally but with their local reputation damaged by Mr Lainchbury's absences and departure.

LABOUR

Labour hold strong hopes of winning the seat having missed out by just 37 votes in the last election in 2007.

However they are approaching the by-election on the back foot, with their party enduring a torrid time nationally and trying to respond to a poor showing in the recent European and county council elections.

If they win they would strengthen their position as the official opposition party, moving to 14 seats, and would look for a leading role if a coalition was formed.

In the early stages of the by-election campaign the group's leader Gill Mitchell was joined by Green Party convenor Bill Randall in saying they would consider working together.

However the campaigning has prompted increased hostility between the members of the two parties and there remain question marks over whether they could work together, or would be prepared to in a formal way.

They have significant differences in some policy areas and deciding who would take senior roles in a coalition would be complicated, with neither party likely to want to play second fiddle.

The position would possibly be slightly clearer if Labour was victorious, giving them the leverage of extra seats.

GREEN PARTY

The Greens have come into the poll bouyantly on the back of a European election campaign which saw them trounce their rivals, and two years after a city election which also saw them surge forward.

They had ground to make up on Labour and the Conservatives, based on the 2007 result, but have been visibly very active in their campaign and are confident of making it a close call at the least.

A win for the party would give them 13 seats, bringing them level with Labour, and continue to instill them with the belief they are a party on the rise both locally and nationally.

They would take it as a strong indication further gains would be possible in the next city elections in 2011.

They already have high hopes for installing the country's first Green MP in the Brighton Pavilion constituency next year.

A Green victory would further complicate the possibility of a coalition with Labour, with neither party being able to pull rank on the other.

The party may also be more reluctant to ally itself if it feels it is on the ascendancy and does not want to have to compromise to join with Labour.

If that is the case it would become a possibility that the rival parties could allow the Conservatives to remain in control but use their greater numbers to form a more powerful, overseeing opposition.

LIB DEMS AND UKIP

The two less fancied contenders in the by-election will by no means be also-rans.

At the very least they are likely to affect voting, and the Lib Dems in particular have performed well in the ward in the past.

The Lib Dems could have a key role to play whatever the outcome. The party's two existing members could find themselves in a position of considerable influence if either Labour or the Greens won – meaning they could tip the balance of the council one way or another.

If they were to secure a third seat with a by-election victory it would extend that possibility.

The Lib Dems have so far been unenthusiastic about forming any formal coalition with the other opposition parties.

A win for UKIP would represent a major breakthrough for the party, bringing their first seat on the council, and would put them in a similar position of overall influence.

Today's polling, and tonight's poll, will be closely watched across the city.