Dealers are warning customers they may have to wait six months or more for delivery of premium models, which means they are running the risk of hitting the higher rate of VAT.

Part of the problem is the growing complexity of vehicle specifications.

For example it is not unusual on a premium badge car to be offered the choice of up to 100 different options, which leads to very few identical examples being built.

An Audi spokesman said customers ordering now will wait typically until the first quarter of 2011 for all model ranges apart from the A4.

As the recession began to bite in the second half of 2008, manufacturers responded by scaling back production and inventories have fallen significantly.

A spokesman for Mercedes-Benz said: “Stock levels around the network are pretty low at present.”

While many premium cars could take six months or more to be delivered, Ford is in a position to satisfy most orders comfortably within four months, and many within three months.

A Ford spokesman said: “Lead times are something the company monitors closely and no car line is running an average of more than 18 weeks.”

Many other mainstream brands seem to be able to satisfy customer demand more swiftly than the premium brands, and in some cases have taken action to ensure shorter times between ordering and delivery.

A Mazda spokesman said the company holds what it calls ‘sold orders’, with dealers reporting quarterly which vehicles they are likely to sell.

Vauxhall also confirmed it is able to meet customer requirements in a similar way.

“We hold a stock of some of the most popular vehicles can supply these within two to three weeks of the customer ordering,” said a spokesman.

“But it normally takes about four to six weeks from a car being built to order to it arriving with the customer.”

Although Volkswagen quote a typical order time of 16 weeks, it says it is sometimes able to respond more quickly and has set up a scheme where cars held in stock can be offered as an option for a shorter delivery time.