Figures out yesterday showed that the final of The X Factor on Sunday, won by Geordie Joe McElderry, was watched by almost 20 million people, making it the biggest series of the talent show so far and one of ITV’s biggest rating successes ever.

Around 10 million votes were cast for 18-year-old Joe and runner-up Olly Murs, which – along with advertising revenue – is expected to earn £18 million for ITV at a time when the broadcaster has been struggling with slipping revenues.

Peter Fincham, ITV director of television, said it demonstrated ITV1 still had pulling power in a multi-channel age.

Yesterday’s viewing figures showed that at its peak 19.1 million people watched The X Factor on Sunday. That was 62% of the TV audience and a big rise on the 14.6 million who saw Alexandra Burke declared winner in the finale last year.

Figures across the 2009 series, which attracted an average of 11.8 million viewers on ITV1 and a 45.4% audience share, are up almost two million on last year.

Across the weekend, when ITV1 also broadcast I Dreamed a Dream – The Susan Boyle Story, the channel averaged a peak-time share of 41.6%, the best performance for ITV1 for a weekend since 2002.

Despite the record figures for The X Factor, it did not match this year’s Britain’s Got Talent final, which peaked at 19.2 million and drew an average of 17.3 million viewers in May.

However, Sunday’s data meant an embarrassing eclipse for the BBC Sports Personality of the Year programme, broadcast directly against the final of The X Factor.

BBC Sport Personality of the Year on BBC1, which was won by Ryan Giggs, averaged 4.7 million viewers, peaking at 7.2 million.

McElderry won almost two-thirds (61.3%) of the votes in the final, compared with just more than one-third (38.7%) for Murs, according to The X Factor website.

Talk has already turned to what happens next for Joe, with some reports suggesting Simon Cowell wants to take him to America to become the next Zac Efron. Asked about the reports, McElderry said yesterday: “I have not heard about this, this is news to me. I wouldn’t turn it down if that was the case. I would give it a go.”

McElderry is now odds-on to win the Christmas number one with his debut single, The Climb. He said winning the competition was the best experience of his life.

“I am still pinching myself, I cannot believe it, that I am sitting here, and that I have just won X Factor. I think it is going to take a long time to sink in.”

Cowell has said he now has plans to take the show to America and beyond. He said shows in Los Angeles and Las Vegas were being lined up and hinted versions for countries such as Afghanistan or North Korea should not be ruled out. He told BBC’s Newsnight the show would go to the US. “To not make X Factor in the biggest market in the world would be crazy,” he said.

Asked if he would sanction X Factor in North Korea, he said he would check the British Government’s policy on working with such countries before running with it.

“On principle, I can’t see it happening, but most places – and you mentioned Afghanistan and places like that, where these shows run and you allow the public to get involved – I think it’s more of a positive thing than a negative thing.”

The 10 million votes cast on Sunday exceeded those cast for the Government in the 2005 General Election.

Asked about plans for some kind of political engagement for The X Factor, Cowell said: “There could be some kind of referendum-type TV show where you can speak on both sides and then open it up to the public to get an instant poll as to how they feel on the hot topics.”