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Malcolm Smith is a Cambridge don who came to McLaren with an idea in 2003. He was fascinated with parallels between electric circuitry and suspension systems, reasoned that a suspension system was just a big circuit. With an electrical circuit you have a resistor, inductor and capacitor.

With a suspension, the equivalent of the resistor is the damper, the inductor is the spring. But there was no suspension equivalent of a capacitor - and Smith was bugged by this. It was from here that he came up with the idea of the inerter, aka the j-damper in F1 parlance.

In fact it's not a damper, it's a device within the suspension that, like a mass damper, evens out load distribution on the tyres and increases grip but which, unlike a mass damper, is part of the conventional suspension. It is this distinction that's led to its acceptance, whereas the mass damper has been banned since mid-'06. A mass damper, as pioneered by Renault, was outside the suspension.

By contrast the inerter is part of the suspension and moves within it. As well as evening out load variations it's also useful in managing the attitude and giving a better compromise of suspension movement (for low-speed grip) and a stable aero platform (for high-speed grip). A car with a stiff suspension - to get good aero performance at high speed - will suffer greater load variation on the tyres at slow speeds than a softly suspended car. The inerter allows the stiff suspension without quite as much penalty in the slow corners.

'Can you give me the 50-zog J-damper'

McLaren developed Smith's idea and raced it for the first time at Imola in '05, initially using it on the rear suspension but in time applying it to the front also. This may have been why McLaren found less advantage than some teams did from the mass damper the following year - in that their inerter was already bringing much of the benefits conferred by the mass damper.

The inerter patent is held by Cambridge University and McLaren entered into an exclusive rights agreement for its use in F1. They took care to keep its existence secret for as long as possible. They situated it in the rear transverse damper, and it comprised a moving weight - which opposes the changes in forces being fed into the tyres by the suspension - attached to a threaded damper, with bearings on its outer face to facilitate its sliding up and down inside the housing.

But this was enclosed so when the damper's external casing was removed, all that could be seen was another casing. Secrecy was also the reason it was given the code of 'J-damper', it being felt that such a misleading label would delay understanding of the device as knowledge of it inevitably leaked to other teams.

Different tracks require different levels of 'inertence'. This is conventionally measured in kg/square metre, although again there was an internal McLaren code to prevent instant understanding and instead of kg/sq metre their engineers spoke in units of 'zogs'. "Can you give me the 50-zog J-damper," could actually mean, "Could you give me the 0.75kg/sq metre inerter." I say 'could' because the precise conversion from kg/sq metre to zogs remains unknown outside a small clique of McLaren engineers.

But other teams cottoned on and within a year or so were devising their own 'J-dampers'. Ferrari were believed to be relatively late onto the idea. It's believed they first used it at Turkey last year, and that Massa's suspension failure at Monza was a failed inerter. Getting the inerter and the damper working together is tricky and if they get out of synch you tend to get an instant breakage of the damper.

An observer might deem it ironic that while in the midst of pursuing an intellectual property infringement case against McLaren, Ferrari were perhaps unknowingly fitting a device for which McLaren held an exclusive use agreement. Which brings us to the point of why McLaren has not pursued its claim against other teams for using their technology.

There were two reasons: one is that they came to realise there was no precedent for applying IP law from the real world in F1 design. Indeed, if patent law were commonly used in F1 it could unstitch its whole fabric - racing technology has always evolved so fast through teams copying and adopting ideas from their rivals. If it wasn't so, a team could become hugely dominant and be legally aided in remaining so. Imagine if there had been an exclusive rights agreement for the use of wings.

Now everyone has it

The second reason was that McLaren feared if it challenged other teams using the technology, it would cause such grief that the governing body would ban it - and McLaren would lose any advantage it had through having been developing the technology longer.

Why did McLaren take out the exclusive use agreement? Probably to slow the dissemination of the idea. Now everyone has it, the agreement will be allowed to lapse.

How significant might it all be? Consider that last year the Ferraris had nothing like the McLaren's pace at Monaco. This was before Ferrari had their inerter suspension. This year, with the inerter, they were every bit as fast.