This UK political party is winning on Facebook

Populist U.K. Independence Party (UKIP) is the most discussed U.K. political party on Facebook, the social media site said Friday, less than a week ahead of the country's closely-run general election.

UKIP, which is in favour of Britain leaving the European Union and implementing tighter controls on immigration, attracted over 15.6 million interactions from 3 million individuals on Facebook between January 1 and May 1, Facebook said. These include likes, comments and shares.

Read MoreUK election: Why the world is watching


In second position was the ruling Conservative Party, with 12.2 million interactions from 2.5 million people, followed by the opposition Labour Party, with 9.7 million interactions from 2 million people.

Facebook said that past studies have shown that debate on the social media site ahead of an election can help increase voter turnout -- and that's something that could make a difference in next Thursday's election.

The Conservative and Labour parties have been running consistently close in the opinion polls, while smaller parties such as UKIP and the Scottish National Party have gained in popularity.

Many analysts expect a hung parliament where no one party has an overall majority to form a government, indicating that both of the country's main political parties need all the help they can get.

According to Facebook, UKIP was also the most talked about party in 35 out of the top 40 marginal seats in the country – in other words those constituencies with a small majority.

The release of the Facebook data coincided with the social media firm turning London's iconic London Eye into a visual representation of how 8.4 million people on Facebook are talking about the main political parties in the U.K.

What If...The UK Had A Presidential System?
What If...the UK had a Presidential system?   

"Politics is huge on Facebook – we expect it to be the most discussed topic in the U.K. this year," Elizabeth Linder, Facebook's politics and government specialist for Europe, the Middle East and Africa, said in a statement.

Facebook added that its data also revealed that the number of people discussing the SNP, led by Nicola Sturgeon, has increased by 61 percent since April 1 – more than any other party.

Sturgeon became the pro-independence party's leader in 2014 after the SNP failed to persuade Scots to vote for independence from the U.K.

The day after an April 2 seven-way leaders' debate, Sturgeon tweeted that she had gained 15,000 new followers on Twitter, in one sign of her impact on voters in the social media sphere.

Read MoreIs this the 'most dangerous woman in Britain'?

Darren Lilleker, an associate Professor at Bournemouth University, whose research focuses on political communication, told CNBC that the parties were taking social media more "far more seriously" during this election, but that it remained "largely a broadcasting tool."

"They use Facebook and Twitter in similar ways to push out messages rather than communicating with their supporters," he added.