Kubica tests this week as

WILLIAMS IS EDGING CLOSER TO finalising its line-up for the 2018 Formula 1 season, with Robert Kubica set to take part in a one-day test at Silverstone this week.

The seat alongside Lance Stroll next season has become the most coveted on the grid, with Williams having received enquiries from several drivers and made its own contact with others.

The Williams board is mulling over four potential drivers for the season: would-becomeback star Kubica, the incumbent Felipe Massa (above), ex-force India and current DTM racer Paul di Resta, and Mercedes protege Pascal Wehrlein. Wehrlein’s Sauber team-mate Marcus Ericsson and dropped Renault driver Jolyon Palmer are believed to be out of contention.

As part of its evaluation of Kubica, who Williams feels could be the top-line driver it requires to maximise the potential of next year’s challenger, the team will run the one-time F1 winner in a 2014-spec car, which has been used by Stroll for circuit familiarisation during last season and at tests this year.

Renault ran out of time to do further testing with Kubica when Carlos Sainz Jr, who the team had chased since last year, became available. Williams is now picking up the baton with a more targeted testing programme. The 32-yearold Kubica is keen get more mileage as his confidence in an ability to return to F1, following his 2011 rally accident, continues to grow.

Kubica will complete a day at Silverstone, followed by another one-day test at the Hungaroring – where he drove a 2017-spec Renault for a day during in-season testing in August – ahead of the United States Grand Prix.

Williams reserve di Resta will also get a run out in the 2014-spec Williams before the Austin race. He has been pushing for a return to a full-season race seat for the first time since

2013, when he left Force India, after a strong performance as Massa’s stand-in at this summer’s Hungarian GP.

The team wants to give him a chance to get some proper mileage as well as giving it data to compare with Kubica. Should Williams ultimately choose Kubica, it could sign 31-year-old di Resta as a reserve again and slot him in to replace the Pole if required next season.

But Massa has said that running Kubica and di Resta in 2014 cars will not give Williams enough information to judge their potential.

“It doesn’t change anything for me,” said

Massa, who is in his fourth season of racing for Williams after being coaxed out of retirement for this term when Mercedes snapped up Valtteri Bottas to replace the retiring Nico Rosberg.

“Even if you do a test with cars that are four