SUSIE WOLFF says she will not give up on her Formula One dream but admits she faces an uncertain future in the sport after completing her second and final scheduled practice outing of the year for Williams at Silverstone.

The Scot finished 13th in the opening session ahead of tomorrow's British Grand Prix.

Twelve months after her practice debut was restricted to four laps by a technical fault, Wolff, who joined Williams as a development driver in 2013, completed 19 laps yesterday.

However, she admitted it is a slight concern that she has no more track outings scheduled. The 32-year-old said she is prepared to accept her fate if no seats open up but added that she will keep on fighting for her chance.

Wolff said: "It's the beginning of July and the team are not thinking of next year yet and I'm not really thinking of next year either. I have a lot of work to do in the simulator before the end of the year.

"The feeling right now is I'm happy to have gone out in a solid way and finished with a good session. Let's see what comes.

"But I'm someone who always said I need to make progression in my career. I need to keep going, I can't just keep waiting on the cusp. If there's no realistic way that I could get myself on the grid then I'm going to have to face that reality.

"I'm thankful for the opportunities I got this season. Thankful for the fact that I got to go out in an F1 grand prix weekend and give it all that I could and show what I was capable of.

"I was highly motivated. The team did a really good job of getting me ready and immediately the car felt good.

"It is a bit worrying there's nothing else planned, but I'll stay in the fight and only when I think that I have no chances left will I look for something else."

Asked if she was talking to other teams about what opportunities might be available for 2016, Wolff added: "Right now, no. I was fully immersed in getting ready for my outings with this team and I think some people underestimate the work that goes on in the background.

"The days in the simulator back at the factory, the training sessions which go in to make you ready to jump into an F1 car and go for it, that is a lot of work that goes on behind the scenes. And it doesn't give you the capacity to do a lot of other things.

"Williams gave me my chance in F1. It was only ever a one-off test and it turned into more and right now my focus is on doing the best job I can do for this team."

Nico Rosberg topped the timesheets for both of yesterday's sessions, overcoming a hydraulics failure in the morning to pip his Mercedes team-mate Lewis Hamilton.

However, Hamilton was only fourth in the afternoon, behind the Ferraris of Kimi Raikkonen and Sebastian Vettel as well as Rosberg.