Given that her TV appearances these days seem limited to a news soundbite whenever the latest of her contemporaries gets either Yewtreed or convicted, it’s hard to imagine that Cilla Black was once hot showbusiness property. But here she gets the weighty three-part drama treatment from ITV, the channel which housed her greatest light entertainment hits, Blind Date and Surprise Surprise.

This near three-hour puff piece shows just how far the ITV drama department is capable of plummeting. Reports had suggested that Black threatened to withdraw her full co-operation if writer Jeff Pope included any ‘smutty’ scenes. So, the fruitiest this gets is when her father accuses Cilla’s eventual husband Bobby Willis of leaving a stray sock in his daughter’s bedroom.

But over 180 minutes, there simply has to be some shade in such a boundlessly light affair. And so she does come across as a bit mean over Bobby’s own ambitions to be an onstage star, cruelly halting those dreams in their tracks by insisting that he carry on as her ‘road manager’. The underlying suggestion is that these actions were down to this national treasure feeling the intense pressure of trying to maintain her own early success of two successive number one hits and attempting to force her way into the American psyche; not easy when the influential likes of Ed Sullivan introduced her on his show (watched by 30m viewers) as being ‘from Wales in England’.

As Cilla, Sheridan Smith does her utmost to inject a bit of soul into proceedings, but with such bland raw material to work with, both the actress and the drama are on a hiding to nothing. The closest this gets to stirring scenes of social commentary come when Bobby’s father feels a little let down that his son has chosen to get involved with a Catholic girl. And the most emotion that is wrung from Smith arrives when she is asked to look distraught after singing badly for her ad hoc audition in front of Beatles boss Brian Epstein. So humdrum was her offstage life that more focus is put on Epstein’s sexuality (he had a predilection for a spot of bruise-leaving S&M) than you’d think was necessary in anything other than his own biopic.

Smith does a decent job (the cosmetics department deserve credit for those gnashers) and Aneurin Barnard (the absolute spit of Douglas Henshall) is fine as Bobby. But the bar is raised by Ed Stoppard who is excellent as the tormented Epstein, and there are some nice cameo touches from Elliot Cowan as a very patient George Martin trying to take the north out of her vocals and Daniel Pirrie as an overly-demanding Burt Bacharach. But these small mercies are just not enough to save such an insipid piece. Unlike the woman herself, Cilla lacks bite.

Cilla starts on ITV1, Mon 15 Sep, 9pm.