Imagine you grew up in a world without The Beatles - it's easy if you try.

That's the exact situation singer-songwriter Jack Malik (Himesh Patel) finds himself in director Danny Boyle and writer Richard Curtis's new musical romantic comedy, Yesterday.

Jack, a wannabe troubadour who can't escape East Anglia, despite the loving attention of his manager Ellie Appleton (Lily James), wakes up from a coma following a serious bike collision, only to discover that he's the only person to remember John, Paul, George, and Ringo ever existed.

After receiving plaudits from his pals for playing several bars of Yesterday (which they believe is a brilliant new composition), Jack decides to set off on the long and winding road to fame by working out how to play The Beatles' biggest hits and pass them off as his own.

Initially, his career as a bootleg Beatle looks to be following a similar path to his earlier failed efforts, with classics like Let It Be seemingly destined to only be heard in his parents' living room. One pub performance, however, does impress a small indie producer (Alexander Arnold) who gives him the chance to record an EP.

After performing In My Life on local TV, he is spotted by Ed Sheeran, who takes him on tour to Moscow where a stirring rendition of Back in the U.S.S.R. and his victory in a 'songwriting' competition with the ginger pop idol impress Ed's ruthless manager Debra (Kate McKinnon), and set him on the road to stardom.

It's an intriguing, if not entirely original premise. In time-travelling sitcom Goodnight Sweetheart, the main character tries a similar trick in 1940s London, while David Quantick's black comedy short Snodgrass imagined a world where John Lennon left The Beatles in 1962, leaving him unemployed and bitter in middle-age, and them as middling Merseybeat exponents.

However, it's one that seems wasted in this saccharine romcom. For a film in which Jack is constantly telling us of The Beatles' inherent greatness, it doesn't seem to love them enough.

A visit to Liverpool, a few brief glances at Penny Lane or Strawberry Fields excepted, is mostly spent in the hotel, station rather than the Cavern Club, while Curtis's script, one good gag about Oasis aside, largely ignores the wealth of material you could mine from the Fab Four's unique history. This means that its lionisation of their groundbreaking hits feels a bit like a hastily pulled together Spotify playlist rather than a fitting tribute.

This might not matter if its satire of the modern music industry had some edge, but Yesterday wants to have its cake (or Savoy Truffle, if you prefer) and eat it. Sheeran's performance is as wooden as his acoustic guitar, and though he attempts a bit of self-mockery, we're never more than a few lines away from being informed of his, as well as The Beatles' genius.

McKinnon breathes some life into the ogreish Debra, but the jokes about the perils of fame and the shallowness of the music industry feel superficial in a movie that delights in celebrity enough to bring in James Corden for a needless cameo. This effectively leaves a traditional Curtis romcom adorned with Beatles songs, centred around a Jack and Ellie's stilted, abortive relationship.

Both leads' performances actually go some way to rescuing the film, as James displays the tenderness and comic chops we saw in Baby Driver and Mamma Mia! Here We Go Again, while ex-EastEnder Patel's soap background stands him in good stead as a believable everyman. However, James's character, despite starting the film as his manager, is given little to do other than to be the girl Jack must get back.

Yesterday is not an absolute disaster. Those who like their romcoms sweet with a little sprinkle of Sgt. Pepper's might find it a diverting experience. But from the director of Slumdog Millionaire one expects better, and the Fab Four should be getting better from him and Curtis too.