Despite showing that she deserved a drive on merit, Guthrie would never compete on a level playing field at Indy, without access to the funding and support that leading drivers enjoyed.

In 1978, she set up her eponymous squad for the Indianapolis 500 – the most difficult Month of May she had.

“It’s a very expensive sport and it takes a lot to assemble a team, to run a full season, I would’ve loved to have had that opportunity,” she says.

“When I did assemble my own team in 1978, and ended up with a top-10 finish that year [ninth], I did it on a budget of about 5 per cent of a top team running a full year. It was no secret, I did it for $120,000.

“I had all the duties, obligations, responsibilities of a team owner as well as going out to drive the car, and especially under last-minute circumstances that really was tough. Driving the car was definitely the easy part.”

Janet Guthrie and her crew at the 1978 Indy 500 Motorsport Images

Underlining just how hard it is to be a driver/owner, Guthrie had a fractured wrist during the race (for which she was later reprimanded by officials), having to steer, change gears with a broken gearbox, and use a radio for which the volume button vibrated closed during the race.

“OK, so you needed one hand for the steering wheel, one for the gearshift and had I had a long prehensile tail to operate the radio I would’ve been fine,” she says nonchalantly.

Guthrie may shrug off the difficulties that she faced, but is in no doubt about the challenge that the Indianapolis 500 still represents, even to a well-funded team, such as McLaren, which failed to qualify with Fernando Alonso this year.

“I empathise [with McLaren],” she adds. “It’s happened before. There was one year where Roger Penske astonished the whole world when his cars did not make the field at Indianapolis. The guy who walked on water and his cars aren’t making the field? People have forgotten that that happened.”

More than forty years after Guthrie first raced at the Indy 500, there’s now only one woman in the 2019 field: Pippa Mann, who starts 29^th on May 26. So, has the motor sport world done enough to let the women with talent compete?

“No I don’t think we have come far enough,” says Guthrie. “Pippa Mann is a very capable driver with a very good record, but you can’t drive Indianapolis 500 as your only race of the year with a backmarker team and expect to run up front, that’s not going to happen that way.”

So what is the solution to the lack of women – not just in the Indy 500 field – but all over motor sport? Not W Series, says Guthrie.

“[The all-female W Series] seems to me to indicate that we’re not capable of competing with men which isn’t the case,” she says.

“I see that they have filled the field because there are so many women who will do practically anything to get their hands on a car but I don’t think it’s a good idea actually.

“The women with the ability are out there, it just depends on who gets the chance. There’s a young woman named Hailie Deegan who has two wins in NASCAR’s lower level K&N Series so I have my fingers crossed for her and women like Simone de Silvestre, Katherine Legge, they’re there.

“Sarah Fisher is retired now but she absolutely had the capability to win IndyCar races; she just never found the money. So it is possible, I just hope it’ll happen sometime soon.”

Janet Guthrie in the pits, 1979 Indy 500 IMS

The problem is systematic, she argues, not just in grassroots motor sport, but at the top level where women aren’t in the position to make decisions to sponsor talented drivers, whatever their gender.

“As we get more and more women in executive positions in business, I hope more of them will see the advantage in having a woman driver represent their business and their product, and more and more women are coming into the executive level, so I hope that has a beneficial effect.”

Janet Guthrie documentary

Guthrie appears in a feature-length ESPN documentary – Qualified – produced and directed by Jenna Ricker and co-produced by Caroline Waterlow and Nina Krstic – both Academy Award winners for OJ: Made In America.

“One of the things that fascinated me about Janet and racing, in general, is that it’s one of the only sports when once the helmet is on and the driver is in the car, nobody can tell if it’s a man or a woman,” says Ricker.

“And it’s brilliant. It’s one of the best things about it. The car does the heavy lifting, and so it is an area where men and women can compete on an equal playing field so it would be a pity to start separating that,” she says.

“Young women coming up racing sprint cars, go-karts, when they reach around 14 years old they’re told ‘you have to start making decisions, do you want to go to college or do you want a family? You can’t do that and race.’

“Young men are not told that, so there becomes this split that happens at a young age as well. We have to work towards the middle.”

Janet Guthrie on the Indianapolis pit wall, 1978 Motorsport Images

The documentary comprises archive footage filmed on Super 8 cameras by Guthrie and her brother Stewart Guthrie, also including interviews with the likes of Johnny Rutherford, AJ Foyt, Tom Bigelow, members of Janet Guthrie’s crew and of course, the driver herself.

“I’ll tell you,” continues Ricker, “the worst part was the stuff we had to leave out. That’s always the killer.”

And a biopic might be in the works. It’s just the matter of casting someone worthy enough to play Janet Guthrie.

“Well over the years I’ve wondered who might play me in a movie but they all keep getting too old!” says Guthrie.

“The last one I thought of was Gwyneth Paltrow and what interested me about her, I read that when she was young she thought of herself as being homely. And I thought, that’s rather intriguing… “

So does Janet Guthrie think Paltrow is right for the role? She chuckles, pondering the similarities between her and the actress and says: “oh me? I’ve never been a raving beauty!”

ESPN’s documentary – 30 on 30: ‘Qualified’  – aired on BT Sport in the United Kingdom.