The team tumbled from fifth to 10th in the world championship, which has led to a drop in this year's income from the F1 organisation.

In addition, it has lost the income associated with drivers Lance Stroll and Sergey Sirotkin, as well as previous title sponsor Martini.

However, it has gained a new title sponsor in ROKiT, as well as Orlen sponsorship from Robert Kubica.

Nevertheless, the F1 team generated revenue of just £46.3m in January-June, compared with £60.7m last season, generating an EBITDA [earnings before interest, tax, depreciation and amortisation] loss of £16.8m, after posting a profit of £0.2m in the same period last year.

The F1 figures were offset in part by an improved performance for sister company Williams Advanced Engineering, which increased its revenue from £21.5m to £30.9m.

Total combined revenue for parent company Williams Grand Prix Holdings fell from £82.6m to £77.8m, with the overall EBITDA loss increasing from £2.7m to £18.8m.

"Our financial results reflect a challenging half year for our F1 operations, yet also demonstrated continued growth in the Williams Advanced Engineering business," said group CEO Mike O'Driscoll.

"The F1 financial results primarily reflect our finishing position in last year's Constructors' Championship and the consequent reduction in prize money (which is paid a year in arrears).

"There was also an overall reduction in partnership income compared to the first half of 2018, although we secured major new partnerships with ROKiT and Orlen.

"Although we are enduring another tough season on track, we have seen some recent signs of improvement, and we continue to attract interest from potential partners as one of the longest standing Formula 1 teams.

"This is best demonstrated by the recent two-year extension to our title partnership deal with ROKiT who will now continue with us until at least 2023."

Williams will clearly take another big hit on F1 income next year as it heads for a second successive 10th place in the championship.

However, O'Driscoll remains bullish about future prospects, stressing the importance of the 2021 regulations.

"Negotiations with Formula One management and Liberty Media regarding the future of the sport from 2021 have been productive and we believe, when finalised, will represent a much-needed opportunity for Williams to benefit from a more level financial playing field, as well as new technical regulations."

He added: "Although we continue to face challenges in a very dynamic environment, we currently believe the majority of the impact on EBITDA for the full year has already been captured in these interim results.

"We continue to believe we are well placed to respond to the challenges ahead, with world class facilities and a strong and talented organisation."