The wording of F1's ban on in-season testing has been clarified.

Red Bull team boss Christian Horner recently said Ferrari's use of a filming and promotional track day to test updates for the F10 car was "naughty" and breached the "spirit" of the agreement.

And FOTA chairman Martin Whitmarsh suggested that other teams including Mercedes and Renault have also made "some arguable decisions" with regards to the rules about in-season testing.

"If people want to be more comfortable then I know there are discussions in order to tidy up the wording, and I have no problem with that," said Ferrari team boss Stefano Domenicali.

Italy's Autosprint reports that during a meeting at Silverstone last week, the teams drafted new wording to prevent the testing of new components during promotional or filming days.