Formula 1 has launched a staggering attack on the president of its own governing body by accusing Mohammed Ben Sulayem of "unacceptable" interference.F1 chiefs were responding to a series of tweets from the FIA president on Monday in which he described a £16.2 billion valuation of the sport as "inflated".But in an explosive letter, composed by F1's legal team, sent to the FIA's World Motor Sport Council, the grid's 10 teams, and leaked to Sky News, Ben Sulayem has been described as "overstepping the bounds of the FIA's remit".The FIA was also told it could be held "liable" for harming F1's owner's (Liberty Media) value.Escalating tensionsF1's reaction to Ben Sulayem's social media posts is a dramatic escalation in tensions between the sport and the FIA.Last week, Bloomberg News reported that Saudi Arabia Public Investment Fund explored the possibility of a $20bn takeover of F1.American conglomerate Liberty Media ended Bernie Ecclestone's reign when it bought F1 from private equity firm CVC Capital Partners for £6.4bn in 2017.READ: FIA president blasts reports of selling F1 for $20bn: 'Apply common sense'Ben Sulayem, who has been president of the FIA for 13 months, tweeted: "As the custodians of motorsport, the FIA, as a non-profit organisation, is cautious about alleged inflated price tags of $20bn being put on F1."Any potential buyer is advised to apply common sense, consider the greater good of the sport and come up with a clear, sustainable plan - not just a lot of money."It is our duty to consider what the future impact will be for promoters in terms of increased hosting fees and other commercial costs, and any adverse impact that it could have on fans."As the custodians of motorsport, the FIA, as a non-profit