FIA president Max Mosley believes that the principal of freezing engine development will continue to hold sway in Formula One, despite his much-vaunted push for a single 'spec' engine in the top flight.

The latest step in Mosley's 'masterplan', the announcement that long-time F1 supplier Cosworth had secured the tender for any future one-make engine, coincided with - and was therefore overshadowed by - the surprise exit of Honda from the top flight, but the president has since admitted that he does not see the British manufacturer having a monopoly over engine supply.

"The plan, of course, was not so much a single engine, as for a single level of performance and a much cheaper engine," he told the official F1 website, "This will become increasingly necessary if we lose any more manufacturers. The withdrawal of Honda was a surprise. They were good enough to inform us in confidence four days before announcing it, but they would have been one of the last teams I would have expected to withdraw."

Admitting that the fear of losing more manufacturer teams from F1 had been part of the reason for his push towards uniformity on the engine front, Mosley conceded that the exact path to be taken by the category had still to be determined, with some of the staunchest manufacturers threatening to pull out if the spec engine plan is implemented. Alternative suggestions have included allowing the manufacturers to formulate their own method of ensuring that enough low-cost engines are available for customer teams, and allowing the manufacturers to build and badge powerplants to the same spec as that being proposed by Cosworth.

"This is still under discussion, but I think we will end up with a frozen engine, regulated in such a way that independent teams can obtain inexpensive supplies," Mosley admitted, "I think we ought to try to have at least one independent outside engine supplier, because of the risk that we will lose another manufacturer or even two."

The last two years have seen F1 operating under frozen engine specifications, but Mosley also admitted that the plan to bring each V8 unit into line in terms of uniformity of power had been scuppered by the allowances made to teams to tinker with their powerplants.

"The only problem with the original engine freeze was that in rectifying reliability problems, some teams appear to have gained somewhat in performance," he conceded, "We simply intend to ensure that the sporting contest remains fair."

Revealing that he would also be open to the use of 'customer cars' - a thorny issue that has threatened to see F1 dragged through the courts in recent months - Mosley attempted to defend his push for the inclusion of KERS technology from 2009, despite the fact that research and development of the systems has pushed up the cost of competing at a time when the FIA is actively encouraging teams to cut back on what they spend, with drastic changes being made to the development of aerodynamics in an effort to curb outlay and improve on-track action.

"The 2009 aerodynamic regulations were developed by three of the top Formula One engineers, aided by an extensive wind tunnel programme [and, while] I have no means of judging whether they have got it right, if they have not, it will be surprising and disappointing," the president opined, "In addition, the KERS system, if fitted, will make a significant difference to overtaking by giving a car an 80hp boost for up to six seconds each lap.

"The purpose of KERS is to engage Formula One in research in an area which is relevant to road transport and society in general. They have spent far less money on KERS than they waste on Formula One-specific aerodynamics and gearboxes which are irrelevant to the real world. However, KERS is not compulsory and it has always been open to the teams to work together on a common KERS.

"Personally, I have no problem with customer cars. Without them, Formula One in the 1970s could not have flourished. I think the current problem is finding enough competitive teams, without worrying too much about where they get their cars."