Ulster leaders cast their votes
Northern Ireland's political leaders have cast their votes in an election that could hand some of them a role in shaping the next government.
Democratic Unionist leader Peter Robinson cast his ballot in east Belfast while Sinn Fein's Martin McGuinness voted in his native Londonderry.
SDLP leader Alasdair McDonnell was accompanied to a polling station in south Belfast by his wife Olivia while Ulster Unionist leader Mike Nesbitt cast his vote in Gilnahirk in the east of the city.
Alliance deputy leader Naomi Long was joined by husband Michael as she voted in a primary school in the heart of the East Belfast seat she is hoping to retain.
Polling stations in Northern Ireland's 18 constituencies opened at 7am and will close at 10pm.
With the race to get into Downing Street potentially coming down to a handful of seats, the post-election intentions of the region's parties have come in for heightened scrutiny.
In 2010 the DUP secured eight of the 18 seats, Sinn Fein five, the SDLP three, and the Alliance Party and independent Sylvia Hermon had one each.
With Sinn Fein insisting its century-old Westminster abstentionist policy will remain, the DUP claims it is best placed to exert influence in any hung parliament.
It has stated a willingness to back either Ed Miliband or David Cameron depending on what they offer Northern Ireland.
At times during the campaign the DUP saw its message obscured by a controversy over anti-gay comments made by Stormont health minister Jim Wells - remarks that ultimately prompted his resignation.
The SDLP is traditionally aligned with Labour, so would be expected to support Mr Miliband if requested.
While the Alliance Party has links with the Liberal Democrats, its sole MP Mrs Long sat on the opposition benches in the last parliament.
An electoral pact with the Ulster Unionists has boosted the DUP's chances of seeing deputy leader Nigel Dodds retain North Belfast and Gavin Robinson recapture the East Belfast seat his party leader and namesake lost to Mrs Long in 2010.
The SDLP's Mr McDonnell could face a challenge to hold on to his seat in South Belfast, with the DUP's Jonathan Bell and Sinn Fein's Mairtin O Muilleoir both hoping to poll well.
Elsewhere the traditional razor-edge battle for Fermanagh and South Tyrone will command attention.
Sinn Fein's Michelle Gildernew won by just four votes in 2010 - a margin reduced to a solitary ballot paper after review by the electoral courts. This time round she faces off against Ulster Unionist Tom Elliott, another of the DUP and UUP's four agreed candidates.
Upper Bann and South Antrim are also shaping up to be hard fought.
The outgoing DUP MP in Upper Bann, David Simpson, is facing a significant challenge from the UUP, with Sinn Fein also hoping to contend, while his party colleague in South Antrim, Willie McCrea, is set for a wrestle with the Ulster Unionists to hold on to his seat.