IT'S one of the most unlikely recipes for success ever.

Take mostly instrumental music, samples from public information films, archive material, and vintage film footage.

Yet the resulting blend has seen Public Service Broadcasting become not only critical darlings but chart hits too, with new album The Race For Space lifting off and nearly hitting the Top 10.

"I was surprised at how well the first record did so I was even more surprised at this one just grazing the Top 10," admits guitarist J Willgoose, Esq.

"If you sat down and tried to make an album to reach No 11 in the charts, I don't think anyone would make the album we did.

"It's really weird how it has found modest commercial success despite being such a strange concoction of ideas and methods.

"It's quite pleasing that there's enough people out there who are prepared to buy into something different."

Given that the duo, also made up of drummer Wrigglesworth (not their real names, obviously...) will play a packed O2 ABC on Saturday night it's clear there's growing demand for what they provide.

If 2013 debut Inform-Educate-Entertain served as the perfect introduction to the band's sound, then Race For Space expands it further.

Using the space race between America and the Soviet Union as a starting point, it weaves together post-rock, funk and even pop to tell the story of one of history's most fascinating periods.

The guitarist reckons musical expansion was needed to help prove they weren't just a novelty act.

"I didn't want to repeat old ground or get stuck in a rut," adds J, who deliberately keeps his offstage person cloaked in mystery.

"Especially because, more so than other bands after their first albums, there was a lot of doubt cast on us because of the nature of what we do.

"I think a lot of people tagged it as gimmicky, so I wanted something that was musically strong as well as thematically strong.

"We spent time trying to expand, and being a bit more ambitious, and the theme of the space race helped that, because it was so massive that we could take a few steps in our own sound as well."

The album takes inspiration from both East and West, from the exploits of Yuri Gagarin to speeches by John F Kennedy.

One stroke of good fortune occurred when the British Film Institute, who the band work closely with, happened to acquire high quality footage of the Russian space programme.

There's a melancholy note too, with final track Tomorrow dealing with the Apollo 17 mission in 1972.

"I do find it quite sad that it's been over 40 years and we haven't returned to the moon," says J.

"It's important to continue with manned space exploration and to drive forward as a species.

"We got a lot of questions around the times of the first album as to whether we were nostalgic, and we've never been about that - with new technology we can reframe the past and tell its own story, but I've never wanted to be in any age other than now, with the possible exception of the space race.

"It must have been a fascinating time to be alive."

Speaking of interesting times, the twosome found themselves on the road with unlikely partners earlier this year, in the form of an arena tour with the Kaiser Chiefs.

"I think they wanted their fans to experience something a bit different," adds J.

"I was speaking to Peanut (Kaiser Chiefs keyboardist) and he said they'd spotted us at a festival in Holland and just liked what we were doing

"It's fair to say we did split a few audiences along the way, but it toughens you up a bit and makes you a bit less sensitive to abuse."

Public Service Broadcasting, O2 ABC, Saturday, £18.50, 7pm