The prototype of a solar-powered plane destined for a record round-the-world journey will make its first trip across a runway on Thursday and Friday.

This week saw the Solar Impulse plane outside its hangar for the first time, with tests of its engines and computer.

The plane's maiden flight is scheduled for February, and a final version will attempt to cross the Atlantic in 2012.

As wide as a jumbo jet but weighing just 1,500 kg, it will be piloted by Swiss adventurer Bertrand Piccard.

"It's very exciting, we are moving now toward a very concrete phase," said Solar Impulse chief executive Andre Borschberg.

"You have to realise this airplane is quite special and you cannot just put it on the runway, apply full power and go in the air - it has to be done really step-by-step," he told BBC News.

Wright stuff

To that end, the team has spent several days ramping the plane's engines up to full power, and the "taxiing tests" of Thursday and Friday will give the test pilot a feel for how the plane moves on the ground.

If the tests are successful, the next step will be a short hop in about two weeks' time.

"We'll take off at the beginning of the runway, fly a few metres above it - a little bit like the Wright brothers did in 1903 - and then land again, to see how it behaves at the beginning of the flight.

"If this is satisfactory, we will dismantle it and transport it to [Payerne air force base in western Switzerland] where will we do the real first flight of about two hours, in February."

But each step will be a careful one, Mr Borschberg stressed.

"This is truly a new design - an airplane the size of an Airbus and the weight of a mid-sized car - so we're not taking risks by not understanding something."

Glenister's character was blunt and brash

Marks and Spencer's Christmas advert featuring Ashes to Ashes actor Philip Glenister has been branded as sexist.

The Advertising Standards Authority is looking into eight complaints from viewers about the "Christmas wouldn't be Christmas without..." ad.

Glenister, who played chauvinist DCI Gene Hunt in the BBC show, says: "That girl prancing around in her underwear."

The ad cuts to a model, wearing a bra and knickers, who asks: "Moi?" M&S said the complaints had come as a surprise.

'Demeaning'

The French underwear model Noemie Lenoir, who twirls around in a winter woodland scene, is a regular in Marks and Spencer's advertising campaign, alongside Myleene Klass and Twiggy.

An ASA spokeswoman said eight people had been in contact to complain that Glenister's comment, coupled with the shot of Lenoir in her underwear, was demeaning to women.

The advertising watchdog will now consider the complaints and decide by the end of next week whether to launch an investigation.

The 50-second commercial also features several other big TV names, including Stephen Fry and James Nesbitt, who each say what they could not do without at Christmas.

In one segment, Jennifer Saunders says "stuffing" and Joanna Lumley, her co-star in BBC comedy Absolutely Fabulous, adds: "...your face, sweetie."

A spokesman for Marks and Spencer said: "We're surprised by the ASA complaints regarding Philip Glenister's appearance in our TV ad.

"Our research shows that his on-screen character in Ashes to Ashes is extremely popular with our customers and his lines in the ad are in keeping with that role." BBC