Who's who: A look at leading figures in the tightly fought British election

Liberal Democrat Party leader and Deputy Prime Minister Nick Clegg speaks to party activists in Bearsden, Scotland, on the last day of the General Election campaign, Wednesday May 6, 2015. Britain's political candidates are campaigning all across Britain in search of votes ahead of the May 7 General Election. (Steve Parsons / PA via AP) UNITED KINGDOM OUT - NO SALES - NO ARCHIVES (The Associated Press)

UK Independence Party leader Nigel Farage enjoys the sea breeze as he looks out over the harbour during a walk about in Ramsgate, south England, on the final day of his campaign trail, Wednesday May 6, 2015. Britain's political candidates are campaigning all across Britain in search of votes ahead of the May 7 General Election. (Gareth Fuller / PA via AP) UNITED KINGDOM OUT - NO SALES - NO ARCHIVES (The Associated Press)

Labour Party leader Ed Miliband makes a speech to party activists during a General Election campaign stop at the Muni Theatre in Colne, north west England, Wednesday May 6, 2015. Britain holds a General Election on Thursday. (Chris Radburn/PA via AP) UNITED KINGDOM OUT NO SALES NO ARCHIVE (The Associated Press)

Britain's general election is on Thursday, and polls suggest the race between Labour and the Conservatives is too close to call. Here's a look at the leading figures in the campaign:

DAVID CAMERON: Prime Minister David Cameron of the Conservative Party is trying to preserve his place at the storied 10 Downing Street residence. He has led a coalition government for the past five years, steadfastly pursuing a fiscal austerity program aimed at bringing down Britain's budget deficit and high public debt. Cameron, 48, was educated at Oxford and worked in public relations before entering politics full time and becoming party leader in 2005. He brought the Conservatives back to power in 2010, when the party bested Labour despite failing to obtain an outright majority. He has been criticized for appearing lackadaisical on the campaign trail but has tried to fire up supporters by warning that his Labour rivals plan to team up with Scottish nationalists in a new government that would put the future unity of the United Kingdom at risk.

NICK CLEGG: Nick Clegg served as Deputy Prime Minister for the last five years but finds himself fighting hard to keep his seat in Parliament. His Liberal Democrats finished strong in the 2010 election but are struggling to maintain their strength in Parliament this time around. The 48-year-old party leader has sought to position the Liberal Democrats in the political center and says the party offers stability and reliability. He is an outspoken advocate of Britain maintaining its place in the European Union. He has studied political theory in the United States and worked as a journalist before entering politics. His personal popularity skyrocketed during the 2010 election, when he claimed to offer the only real choice for change.

NIGEL FARAGE: Nigel Farage, the leader of the UK Independence Party known as UKIP, has risen to prominence by calling for Britain to withdraw from the European Union and take strong steps to lower immigration into Britain. He says immigration has badly stretched public finances, put too much pressure on the National Health Service, and made English people feel uncomfortable in their own country. Farage, 51, is a member of the European Parliament and is fighting for a seat in the British Parliament representing South Thanet. If he fails to win, he has indicated he will step down as party leader. He founded a successful metal trading business in London's financial district before devoting himself to UKIP on a fulltime basis.

ED MILIBAND: Labour Party leader Ed Miliband surprised Britons by challenging his older brother David for the party leadership — and beating him — in 2010. He was seen before that as less experienced and less articulate than his better-known brother, but he mustered just enough support from labor unions to win. The 45-year-old Ed Miliband has struggled at times to project a forceful image and has been hampered by a sometimes awkward manner in front of TV cameras. Early in the campaign, he said he didn't mind being thought of as a geek and was confident he was tough enough to be prime minister. He attended Oxford and the London School of Economics and is the son of Jewish refugees who fled the Nazis. His father was a prominent Marxist intellectual and his home life was steeped in politics and philosophy.

NICOLA STURGEON: Nicola Sturgeon, leader of the surging Scottish Nationalist Party, has generated headlines throughout the campaign with her impressive debate performances and campaign skills. She is not running for Britain's Parliament, but leads Scotland's regional government as First Minister. The 44-year-old Sturgeon has been an articulate advocate for Scottish independence and has said that any British government without Scottish voices would not be legitimate. Her party is expected to win most of the 59 districts inside Scotland, giving it a powerful bargaining position in post-election negotiations. She is the daughter of an electrician and a dental nurse who became a lawyer after training at the University of Glasgow. She became leader of the SNP and first minister of Scotland in November after the party lost a hard-fought referendum on independence from the United Kingdom. Sturgeon's mentor, Alex Salmond, resigned after the failed campaign.