Claire Williams has responded to claims that her team was behind the move for enforced parity for customer engines.

As previously reported, in January the FIA issued a directive aimed at ensuring customer teams have engine performance parity with their works team counterparts.

Though it is believed all the manufacturers were on occasions holding out on their customers, many felt the intended target was Mercedes which in 2017 clearly had a mode that was not available to its customer teams, leaving the likes of Force India as frustrated at the German outfit's superiority as the Ferrari and Renault powered teams.

However, there had also been unease at those teams supplied by Renault, witness the major fall-out between Toro Rosso and the French manufacturer in Brazil last year, yet when it was suggested to Red Bull boss Christian Horner that the Austrian outfit had been behind the FIA's directive he instead pointed in the direction of his Grove rivals.

This afternoon, Williams took to Twitter, to deny the allegation.

"Contrary to comments made recently in the press, we refute any suggestion that we have questioned the parity of the power units provided by Mercedes-AMG HPP," said the Grove outfit, attributing the comment to Claire Williams.

"We are absolutely confident that the power units used by Mercedes, Force India and ourselves are identical in terms of both hardware and software.

"We have an excellent professional and personal relationship with Mercedes, and our focus is firmly on continuing the good work that we have started, as we prepare for the final test in Barcelona this week ahead of the new season."

Shortly after, Mercedes responded to Williams tweets with: "What Claire said. Hundreds of committed people at Mercedes-AMG HPP put thousands of hours of dedication into providing equal power units across six cars."