Susie Wolff to quit motorsport at the end of the 2015 season

Susie Wolff will quit motorsport at the end of the 2015 season.

Wolff, the wife of Mercedes boss Toto, became the first woman to take part in an F1 race weekend in a quarter of a century with a debut Practice One outing at last year's British GP.

After being promoted to Williams' test driver for 2015, Wolff took part in four Friday practice sessions this season, the last of which was at Silverstone in July.

But Wolff was overlooked in March when Williams hired former Sauber driver Adrian Sutil as reserve when Valtteri Bottas suffered a back injury which ruled him out of the Australian GP.

"I think the events at the beginning of the year when Valtteri Bottas got injured and I didn't get put forward that was one moment where I had to face the harsh the reality that it was maybe going to be more difficult than I had anticipated," Wolff told Sky Sports News HQ when asked when she realised she wouldn't become an F1 race driver.

"In the summer after I had driven the car for the last time I looked at my options for next year and I always said if I couldn't keep progressing, and the next natural progression was to be on the starting grid, then I would call it a day and it became clear that I wasn't going to get onto that start grid, so the decision was pretty easy in the end to make."

Wolff joined Williams as a development driver in 2013 but will hang up her gloves at the end of the season at the age of 32. Nevertheless she believes she could have challenged for race wins in F1.

"I am a competitive sportsperson and I wouldn't be doing it if I didn't believe I was good enough," she added.

"I showed everybody I was good enough every time I was in the car and I was in a competitive team, so of course I would like to have thought I was good enough. But I didn't get the chance, I fought very hard for the chance and it didn't come. And that is what I have to live with now."