If the adage "when General Motors sneezes, America catches a cold" is true, the world's economic powerhouse is in danger of going down with pneumonia.

The vultures are gathering over the world's biggest carmaker amid predictions that its sales this month have slumped to a 25-year low.

One estimate has it that registrations have slumped by 26 per cent, which, if true, would give GM a fifth share of the US market, the lowest for more than 20 years.

The fact that the group has notched up record losses of just over £2 billion so far this year is fuelling rumours that one of the greatest icons of American manufacturing is about to file for Chaper 11, that section of the US bankruptcy laws that allows a corporation protection from its creditors while it strives to rebuild its finances.

GM denies that it is bust: but its problems sure are legion.

Not only have sales fallen off a cliff - thanks in part to the seeming end of Americans' love affair with gas-guzzling SUVs, a staple of the US automotive industry - the group is also staggering under the massive £94 billion deadweight of the healthcare and pension liabilities it owes its employees.

On top of that, the Securities and Exchange Commission (Wall Street's rottweiler of a watchdog that makes our own Financial Services Authority look like a chihuahua) is delving deeply into GM's books.

And just to add to the humiliation, Toyota, already the world's most profitable automotive group, is set to overtake GM as the global leader in terms of volumes.

Unfortunately it is obvious that GM does not have a "get out of jail" card up its sleeve in the form of new models that could conceivably help it rebuild its customer base.

It is working on a new generation of so-called Crossover vehicles - motors that have the interior space and off-road capacity of SUVs but which are built on car chassis rather than truck underpinnings.

Problem is, so is everybody else who counts in the American market: Ford, Daimler-Chrysler and Toyota.

The possiblity that the greatest carmaker the world has ever known might, just might, go under shows just how radically the global automotive industry is changing.

And it makes one think that the predication by the late Alex Trotman, the Brit who made it to the top of the Ford tree, that ultimately there will be just six car companies left in the world, two in the US, two in Europe and two in the Far East, could be coming true.

Some in Britain may be thinking we swallowed our own bitter medicine when MG Rover finally rolled over and died in April.

If so, they should think again. GM's woes could ultimately hit Vauxhall in Britain and Adam Opel in Germany.

Throw in Jaguar's, Land Rover's and Aston Martin's exposure to Ford's own pretty dire financial straights and we might soon have to start reaching for the aspirin on this side of the Atlantic.