LONDON - The first songs penned by Rolling Stones Mick Jagger and Keith Richard were so sentimental they were ashamed of them, Jagger told BBC Radio in an interview to be broadcast on Sunday.

"We couldn't write rock songs. We just wrote these crap ballads," he told Britain's Radio Five Live, in extracts of an interview that were released before Sunday's broadcast.

The band's first five hits were all cover versions of songs written by other stars, though imbued with the Rolling Stones flavor.

But manager Andrew Loog Oldham wanted them to write their own material -- and locked Jagger and Richard in a room until they did.

Jagger said the first song they produced, "As Tears Go By," was far from the heavy-rocker image they were cultivating, so they gave it to pop singer and Jagger girlfriend Marianne Faithfull, who had a hit with it.

"It was pop and we didn't record it because it was crap," he said. "We had a successful crap ballad...I can say now it's a wonderful tune, but we didn't think it was that great at the time."

Jagger said he and Richard "were these two rebellious band members, and we would write nice little tunes, but sentimental stuff."

The dynamic song-writing duo -- whose creative skill and tireless drive has kept the band at the top of the notoriously fickle music business for four decades -- finally hit their stride in 1965 with "The Last Time."

"Eventually we got to grips with writing rock tunes, but it took a little time," Jagger said.

A string of hits followed, such as "Satisfaction," "Paint It Black" and "Get Off Of My Cloud."

The group, which began as a rebellion band but has long since become absorbed into the establishment, Jagger getting a knighthood earlier this year, has just released 40 years of remastered greatest hits.

Richard said the band had no intention of slowing down after a lifetime in the rock 'n' roll fast lane.

"Nobody has been scumbag rockers like us and lived to tell the tale. I wouldn't put it past us to keep on rockin'," he said.

Jagger and Richard, who will both be 60 next year, are currently leading the tireless Stones on another U.S. tour.