Rivals creator says people are too tired to have sex these days

"They do exercises. That’s what they do now. They don't have sex any more."

The author is one of the most prolific writers of the last 50 years, but her work has been thrust back into the spotlight recently with the adaptation of her 1988 novel of the same name.

The series has been praised as "puerile, gratuitous and an absolute riot" and a "bra-off, knickers-down delight" by reviewers.

However, not all of the series' naughtiness comes from the source material.

The series opens with a male backside as they join the mile-high club, but Cooper admitted in a recent interview this was not pulled from her novel.

"It’s fun. It’s quite naughty too," she told BBC of the series.

"There is a lot of sex. In one episode they have every member of the cast coupled and fornicating for the next 20 minutes and all of that."

Cooper went on to reveal was giving her novel a re-read to jog her memory of the tale.

"The 80s really were the most fun time," she said.

"Masses of sex, masses of drinking, masses of parties. The younger generation all wish they had been born then."

She elaborated on the differences she sees between the modern day and the 80s in terms of relationships.

"I think women are much tougher, much stronger and much more forthright. And I think men are much, much less macho. I mean, macho has gone. You are not allowed to be macho.

"Women are stronger and men are weaker, therefore there is not so much sexual desire between them," the 87-year-old summarised.

"Everybody jogs. They get up in the morning, they jog all around the countryside for hours. They do exercises. That’s what they do now.

"They don't have sex any more. They are far too tired to have sex now. Jogging is bad for people's love life. Ruinous."