Robert Kubica and Paul di Resta are both to complete single-day tests in a 2014 Williams at Silverstone as they target replacing Felipe Massa at the team in 2018, it has emerged.

The Pole and the Scot have emerged as the leading alternatives to the Brazilian to race alongside Lance Stroll next season and now are set to make their cases to bosses at the Grove-based outfit.

For Kubica, it is a chance to make what would be a highly-emotive return after seeing his first Formula 1 career ended by a rally crash in 2011 in which he sustained severe injuries to his right arm. 

He had been linked to Jolyon Palmer's seat at Renault earlier in the year, completing three outings with the French manufacturer, including a day in the 2017 car in Hungary at the start of August. 

Meanwhile, Di Resta is also looking to relaunch his F1 career after being dropped by Force India at the end of 2013 and has since been the reserve driver at Williams while competing with Mercedes in DTM.

The 32-year-old earned his chance after an impressive one-off appearance in Hungary earlier this year, replacing Massa who was struck by a virus and was forced to withdraw from the race weekend.

As for the 2008 championship runner-up, he has made it clear he wishes to remain at Williams for one more season and even went as far as to suggest those who know motor racing were supporting him in his bid to stay on. 

The main goal for whoever gets the seat will be to likely score the bulk of the team's points towards the Constructors' Championship and help young Stroll as he continues to develop after a gradual improvement by the Canadian throughout his rookie year.