The Diamond Dagger for lifetime contribution to crime writing has been awarded to two authors for the first time after judges “almost came to blows” this year.

Lynda La Plante and James Lee Burke are the joint recipients of this year’s award, which is administered by the Crime Writers’ Association (CWA) and recognises sustained excellence in the genre.

“By an extraordinary quirk of fate, due to our new voting process, this year’s Diamond Dagger is, for the first time in seven decades, being awarded to two authors,” said Maxim Jakubowski, chair of the CWA Daggers’ committee. “If the Booker prize can do it, so can we!”

La Plante is best known for writing the Prime Suspect and Widows television and novel series. Her other series include Lorraine Page, Anna Travis and Trial And Retribution. In 2008, she received a CBE for services to literature, drama and charity. Her memoir is expected to be released later this year.

“La Plante’s Prime Suspect redefined the role of women in police procedurals and made a star of Helen Mirren, while Widows remains a talismanic – and wickedly entertaining – female-led heist caper,” said CWA chair Vaseem Khan.

James Lee Burke’s series about detective Dave Robicheaux spans more than 20 novels. Burke said he was “honoured and humbled” to receive his award. “It is also an honour to have my name among the best mystery and crime writers in the world,” he added.

Khan said: “James Lee Burke’s lyrical depiction of the American south transcends crime fiction – his prose is often considered among the best to have graced the genre. For many, Dave Robicheaux is the very embodiment of the dogged, morally incorruptible detective beset by personal demons – a beautifully rendered character.”

The Dagger judges “almost came to blows this year and for good reason”, said Khan. “Ultimately, they have chosen to recognise two incredible bodies of work that have each, in their own way, made their mark.”

Jakubowski said La Plante and Burke are “both such wonderful and deserving writers who, between them, demonstrate the marvellous diversity of crime writing”.

This year’s choices were decided by a panel of previous winners including Lee Child, Ian Rankin and Val McDermid. Other past winners include Ruth Rendell, PD James and John le Carré. The CWA awards began in 1955 with the first going to Winston Graham, best known for writing the Poldark novels.