On the campaign trail, Barack Obama promised to get a million plug-in hybrid cars on the road by 2015. His own new presidential limousine will be far from green, however.

The Obamobile being prepared for the president-elect is said to be a monster gas-guzzler made by General Motors, the troubled car giant. It will look like a black Cadillac but is built like a tank. A spy photographer who tracks down future car models for magazines snatched pictures of the heavily disguised first-car-in-waiting when it was being road-tested last summer.

The armour-plated car, which has a raised roof, windows up to 5in thick, extra-strength tyres and a body made of steel, aluminium, titanium and ceramics, is thought to be based on a GMC 2500 truck that gets less than 10 miles to the gallon. Three cars are believed to be in production so that two can serve as decoys.

While security is paramount - the car is built to survive roadside bombs as well as gunfire - there are hybrid four-wheel drives on the market, such as Ford’s Mercury Mariner, which some critics believe could have been adapted for the president.

Most environmentalists are in forgiving mood at the prospect of the greenest US president yet. Obama vowed to press ahead with his plans to reduce CO2 emissions while speaking last week to a bipartisan conference on climate sponsored by Arnold Schwarzenegger, the governor of California.

Obama repeated his campaign pledge to reduce carbon emissions by 80% by 2050 and to invest $15 billion a year on energy-saving technologies despite the economic melt-down. “Now is the time to confront this challenge once and for all,” Obama said. “Delay is no longer an option. Denial is no longer an acceptable response.”

Carl Pope, the director of the Sierra Club, the environmental group, believes that America will soon outstrip Britain and Europe as a model green nation. “It’s easier for us to change course quickly because we only have one president,” he said. “If America engages on this issue, we’ll trump Europe quickly.”

John Podesta, the head of Obama’s transition team, said: “I anticipate [Obama] moving very aggressively and very rapidly on the whole question of transforming the energy platform in the US from high carbon energy to low carbon energy.”

He also promised that the new administration would do its best to unpick some of the last-ditch measures by George Bush to lift environmental protections on some of America’s areas of outstanding natural beauty.

In a stealth move, Bush has introduced a flurry of “midnight regulations” in the closing days of his presidency which have outraged environmentalists, including permission to auction oil and gas drilling leases next month on 50,000 acres of land within sight of Utah’s Delicate Arch, a natural redrock bridge.

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