However, following the failure of their next single "Once on a Sunday Morning", which didn't make the UK charts, the Tremeloes took this as a sign that the public had also grown tired of their current musical style.

After writing "(Call Me) Number One", the Tremeloes played it to some friends, who were "universal in their praise, but equally sure that it was the wrong type of song for the group".

The success of the song was a surprise for the group, given their recent releases, with Blakley saying that "people have bought it thinking it was a good record, and not because it was the Tremeloes".

[5] Reviewing for Melody Maker, Chris Welch wrote that "as one of Britain's most respected "straight" groups, they are ready to take risks with material they believe in musically as well as commercially, an approach shared by the Hollies [who had recently released "He Ain't Heavy, He's My Brother"]".

[6] For New Musical Express, John Wells described the song as having "an enveloping heavy rock backing, with muted trumpets and deep brass and towards the end there's an almost psychedelic instrumental passage.