Booker Prize jury defies the rules and SHARES award between Margaret Atwood and Bernardine Evaristo

They are not the first judges to cause a stir in recent weeks.

But the panel awarding this year’s Booker Prize went to enormous lengths to provoke controversy last night – by insisting the coveted literary award was shared.

A remarkable rebellion by the five judges saw the £50,000 prize for fiction split between Margaret Atwood and Bernardine Evaristo.

Londoner Miss Evaristo is the first black woman to win, while Canadian author Miss Atwood also won in 2000.

The judges unanimously refused to pick one winner, despite hours of deliberation, forcing frustrated organisers to make a last-ditch call to the chairman of trustees, Baroness Helena Kennedy, before announcing the award would be shared.

The prize has been split twice previously – in 1974 between Nadine Gordimer and Stanley Middleton and in 1992 between Michael Ondaatje and Barry Unsworth – but in 1993 a rule was brought in to ban jurors from doing so again.

The panel flagrantly flouted that restriction, with chairman Peter Florence saying they had ‘made the choice that best reflects the jury’s experience of the submissions’ and rules ‘should be adaptable to the circumstances’.

Londoner Miss Evaristo (pictured) is the first black woman to win, while Canadian author Miss Atwood also won in 2000

‘The more we talked about them, the more we treasured both of them and wanted them both as winners,’ he said. ‘We all found that we were torn, and it became the only fair representation of our deliberations. Which is why we found the rules inadequate to the problem that we had been given.’

Miss Atwood’s winning novel The Testaments, the eagerly awaited sequel to the dystopian classic The Handmaid’s Tale, was ‘politically urgent’ and ‘beautiful in its depth’, Mr Florence said.

Miss Evaristo’s Girl, Woman, Other, a collection of sometimes interwoven stories from 12 women of colour living in London, was described as ‘groundbreaking’ and praised for showcasing the ‘wonderful spectrum of black British women today’.

The judges were unable to choose between the two after they initially spent three and a half hours deliberating. They told Gaby Wood, the Booker Prize’s literary director, who refused a request for the award be shared. However, after further deliberation the panel stuck to their decision, forcing Miss Wood to call Baroness Kennedy hours before the ceremony began at London’s Guildhall.

It was only after a second call to Baroness Kennedy, which was made on speakerphone so all the judges could hear, that she decided there was ‘nothing they could do’ about the decision.

Miss Wood insisted the controversial outcome would not set a precedent. ‘They essentially staged a sit-in in the judging room,’ she said. ‘It was a rebellious gesture, but it wasn’t a fighting gesture. It was a generous gesture.’

The Testaments sold more than 100,000 copies in its first week, helped by the worldwide interest garnered by The Handmaid’s Tale – particularly after it was adapted into a hit American TV series.

Judges were subject to a non-disclosure agreement to allow them to receive their copies before the novel was published last month.

Miss Atwood and Miss Evaristo beat four others on the shortlist: former winner Salman Rushdie’s novel Quichotte, Elif Shafak for 10 Minutes 38 Seconds In This Strange World, An Orchestra Of Minorities by Chigozie Obioma and Lucy Ellmann, whose 1,020-page novel Ducks, Newburyport consists mostly of a single sentence.

Last year’s winner was Northern Irish author Anna Burns for Milkman, a novel following a teenage girl during the Troubles.