The air turned blue this evening as Tory mayor Boris Johnson's novelist sister Rachel Johnson beat Labour's notorious spin doctor Alastair Campbell to take this year's Bad Sex in Fiction award.

The Literary Review's annual award was presented to Johnson for her novel Shire Hell at a ceremony at London's In and Out club. A lifetime achievement award was also given to John Updike after the American author realised the "unique achievement" of four consecutive nominations for the award.

Johnson was singled out for her novel's slew of animal metaphors, including comparing her male protagonist's "light fingers" to "a moth caught inside a lampshade", and his tongue to "a cat lapping up a dish of cream so as not to miss a single drop". Literary Review deputy editor Tom Fleming was also disturbed by the heroine's "grab, to put him, now angrily slapping against both our bellies, inside".

"You sort of think it might be a typo, but she is actually referring to his penis as him. It's a mixture of cliché and euphemism, but it's also very spirited – A plus for effort," he said. "All the entries were equally awful this year, but Rachel Johnson had the worst metaphors, and the worst animal metaphors."

Johnson said it was an "absolute honour" to win, taking her place alongside former winners including Norman Mailer, Sebastian Faulks and Tom Wolfe. "I'm not feeling remotely grumpy about it. I know that men with literary reputations to polish might find it insulting," she said, "but if you've had a book published in the year any attention is welcome, even if it's slightly dubious attention of this sort."

She received a plaster foot – intended to be an abstract representation of sex, according to Fleming - presented by The Wire actor Dominic West, at tonight's ceremony, attended by 400 guests.

Updike was not present to accept his lifetime achievement award. "Four times in a row is unique," said Fleming. "He's written great sex in the past but this seems to be gratuitous."

Updike, famous for his close attention to sex, was shortlisted this year for his novel The Widows of Eastwick, in which an abundance of sperm greets the performance of oral sex. "She said nothing then, her lovely mouth otherwise engaged, until he came, all over her face. She had gagged, and moved him outside her lips, rubbing his spurting glans across her cheeks and chin," he writes. "God, she was antique, but here they were. Her face gleamed with his jism in the spotty light of the motel room, there on the far end of East Beach, within sound of the sea."

Alastair Campbell failed to get past the judges' first post with his debut novel All in the Mind, as did fellow shortlistees Kathy Lette, James Buchan, Simon Montefiore and Isabel Fonseca.

Johnson praised the award for discouraging authors from using "awful phrases" such as last year's winner Norman Mailer's "soft as a coil of excrement" description of a penis. "The truth is that anyone who writes sex scenes has [the award] at the back of their mind," she said. "It makes you even more self-conscious when you're lubricating your book with sex."

While vowing to attempt to emulate Updike's achievement – "he sets the bar very high" – Johnson admitted that, as yet, her new novel is so far devoid of sexual content.

She is the 16th winner of the award, established by Auberon Waugh to "gently dissuade" authors from including "unconvincing, perfunctory, embarrassing or redundant passages of a sexual nature in otherwise sound literary novels".