Funny Girl is the story of the early career of the vivacious, hilarious Sophie Straw, star of the much-loved BBC situation comedy Barbara (and Jim), the television programme that ran for four series in the mid-1960s, helped define its era and, crucially, does not exist. The imaginative kernel of Nick Hornby’s new novel is a classic Sixties British sitcom somewhere between Marriage Lines and Till Death Us Do Part, starring the sort of person who rarely received top billing in such shows at that time: a bright, beautiful and naturally funny young woman. Barbara Windsor, Sheila Steafel, Eleanor Bron or either Liver Bird: none of them was Sophie Straw, quite.

In fact, Hornby is explicit in naming Sophie Straw’s inspiration and, presumably, his own: Lucille Ball. The young Sophie — actually Barbara Parker from Blackpool — calls her ‘the funniest woman who’s ever been on television’. But, as she notes, all the lead players in the equivalent British comedy shows were men: ‘Tony, Ernie, Eric, Ernie… There was nobody called Lucy or Barbara in that lot.’

However, once Barbara Parker has caught the train to London (in true Billy Liar fashion) and changed her name, Funny Girl is less a novel about the female lead of Barbara (and Jim) and more the rise and fall of the imaginary show itself and the men who wrote and produced it. The book is a fan letter to comedy writers like Ray Galton and Alan Simpson, Eric Sykes, and Dick Hills and Sid Green. Barbara (and Jim) itself is a tantalising prospect, a pre-Alf Garnett sitcom that broke the mould in how it dealt with those two vital Sixties themes, sex and class — perhaps its nearest equivalent would be the original run of The Likely Lads by Dick Clement and Ian La Frenais. It is both plausible and deftly done.

Appropriately, the novelist whose work Funny Girl most resembles is the great and perennially underrated David Nobbs, whose 1975 novel The Death of Reginald Perrin would subsequently be adapted into one of the most memorable sitcoms of its era. Both writers favour subtle, unshowy prose; both are adept at exploring the quirks of the male psyche; neither is ashamed to be populist. And the humour of the novel, along with much of its energy, resides in its bantering dialogue. Like Nobbs, Hornby is very good at allowing his characters to define themselves via what they say and how they repeat themselves — for instance Sophie’s agent, the happily married Brian Debenham, whose catchphrase ‘I’m a happily married man’ is cumulatively disarming, endearing and funny.

Funny Girl may also be read as Hornby’s latest defence of popular entertainment against high-culture elitism. The latter finds expression in the character of the ghastly Vernon Whitfield, a pompous Third Programme pipe-smoking bore who says things like, ‘I love ordinary people individually. It’s ordinary people en masse that trouble me.’ (There’s also a lovely in-joke about the lowly status of Hornby’s publisher Penguin compared with Jonathan Cape, now both part of the Penguin Random House behemoth of course).

I was uncertain whether Hornby is nostalgic for such clear-cut cultural snobbery or whether he believes it is still alive and malign and living in NW3 and the pages of the TLS. But either way, Funny Girl manages to make his case for him, eloquently and entertainingly. Like all Hornby’s best work, it is both hugely enjoyable and deceptively artful. By the end of the book, it made me sad not only to learn that many episodes of Barbara (and Jim) have been wiped and no longer reside in the BBC archives but also to recall they never existed in the first place.