There are no prizes for guessing the turning point of Guy Chambers’ career. Voted the best song of the last 25 years at the 2005 BRITs, Angels not only launched Robbie Williams into the stratosphere, but made its co-writer the hottest hitmaker in the game – setting into motion one of the most prolific partnerships in pop.

“I’d written many songs before that and some of them had got close to being successful, but none of them had been truly ...