The singer, whose real name is Ben Drew, also won most-performed song for She Said.
Presenting the songwriter of the year award at the event on Thursday, Sir Elton John said Drew’s The Defamation of Strickland Banks was the best album of recent years “by a million miles”.
“I’ve played it so many times, I’ve bought countless copies, I’ve given it to friends, I’ve worn it out,” he said.
When accepting the award, Drew said he had written the record “to get through to the underclass that society doesn’t want to talk about. One day I got a letter from a kid who told me my record helped him get through his time in prison and he wanted to be a better person.
“It was at that moment that I realised what I set out to achieve,” said Drew.
Other winners included Tinie Tempah and Mercury-nominated Irish band Villagers. Special awards went to Muse, Steve Winwood, Free founder Paul Rodgers and musicals legend Stephen Sondheim.
Matt Bellamy, the singer from Muse, picked up an international achievement award recognising the band’s achievements worldwide.
Former Free and Bad Company singer Paul Rodgers, who in recent years has performed as Queen’s lead singer, won the outstanding contribution to British music award.
Meanwhile, Napoleon: Total War won best original video game score, composer Dan Jones won best soundtrack for Channel 4’s Any Human Heart and John Powell won the best original film score for How To Train Your Dragon.