Lewis Hamilton’s spectacular but often controversial career suffered a new twist on Saturday when he was stripped of pole for the Spanish Grand Prix because his McLaren team failed to give him enough fuel.

As a result, Venezuelan Pastor Maldonado of Williams will start from pole position for the first time after being promoted from second on the grid while Hamilton, the 2008 world champion, will start from the back.

Defending world champion Sebastian Vettel of Red Bull was set to line up eighth and Australian teammate Mark Webber from 12th.

The 27-year-old Hamilton was excluded from the qualifying results because he did not return to the pits with his McLaren car after setting his fastest lap.

Instead, he followed urgent orders transmitted by the team and stopped out on the track. He required assistance to return to the pits where a one litre fuel sample was to be taken.

A stewards meeting later decided that this was in breach of the regulations and excluded Hamilton, dismissing his team’s argument that this had happened under circumstances of ‘force majeure’.

“This is such a disappointment. Today’s qualifying session was one of the best I’ve ever driven – the whole car was just rolling so smoothly, it felt fantastic,” said Hamilton.

“On my slowing-down lap, my engineers told me to stop on the track, and I didn’t know why. Later, to hear that I’d been excluded from qualifying, was of course extremely disappointing.

“It’s clear that it’s going to be an incredibly tough race. But as I always say, and as I always do, whatever grid position I start a grand prix from, I’ll always race my heart out.”

The race stewards rejected McLaren’s argument that the incident was a case of force majeure.

“The stewards heard from the team representative Sam Michael who stated that the car stopped on the circuit for reasons of force majeure,” said a statement.

“A team member had put an insufficient quantity of fuel into the car thereby resulting in the car having to be stopped on the circuit in order to be able to provide the required amount for sampling purposes.

“As the amount of fuel put into the car is under the complete control of the competitor the stewards cannot accept this as a case of force majeure.”

McLaren accepted the stewards’ decision.

McLaren team chief Martin Whitmarsh declined to explain precisely why Hamilton had been asked to stop.

“There was enough fuel to take a fuel sample, but we stopped the car. There was 1.3 litres of fuel taken out of the car,” insisted Whitmarsh.

Hamilton and McLaren were given a reprimand and a $US10,000 fine at the 2010 Canadian Grand Prix in similar circumstances.

Whitmarsh said Saturday’s drama was due to a problem in the McLaren garage.

“It is a technical problem that happened in the garage that didn’t impede the performance of the car in any way and we stopped when it had 1.3 litres of fuel in the car,” he added.

Hamilton had a best lap of 1min 21.707sec to finish half a second clear of Maldonado.

Fernando Alonso was next fastest in a Ferrari ahead of Romain Grosjean and his Lotus team-mate Kimi Raikkonen.

They were followed by Sergio Perez of Sauber, Nico Rosberg of Mercedes and defending champion Vettel.

Maldonado’s promotion was a great present for team founder Sir Frank Williams, who was celebrating his 70th birthday in the team garage.

“We have worked so hard to understand these tyres and develop our car around them and this is a great step forward for the team. We have such a good spirit and the car feels fantastic,” said Maldonado.

Williams have their first pole since Nico Hulkenberg secured his maiden and sole pole position at the 2010 Brazilian Grand Prix.

It is also the first ever for a Venezuelan driver.