After a year as king of qualifying, Juan Pablo Montoya's Saturday afternoon form has become one of the mysteries of the Formula One season.

The Williams driver was the man to watch over a flying lap last year, starting seven of the 17 races on pole position and roaring round Monza in September with the fastest ever qualifying lap at any circuit.

But the rules have changed since then and the crowd-pleasing Colombian heads for this weekend's British Grand Prix at Silverstone, where last year he led qualifying, still seeking his first pole of 2003.

German team mate Ralf Schumacher has taken over Montoya's mantle and started three of the last four races from the top slot.

It is hard to say which is more surprising -- Montoya's absence from the top of the timesheets or the success of a rival who entered his seventh season in Formula One with one previous pole to his name.

Montoya shrugs his shoulders and says he is not worried. But the fact that Ralf has won the last two grands prix after leading from start to finish is starting to grate.

"I cannot lie and say that I am the happiest person in the world," he wrote in a column for Britain's Autosport magazine after finishing runner-up in France.

"I am a Formula One driver and I want to win all the time.

"Finishing second was fantastic but it's obvious that I want to beat my team mate Ralf Schumacher just as much as I want to beat everybody else."

EXPERIENCE COUNTS

At the start of the season it was Ralf who struggled with the new qualifying format, which involves drivers running alone and on different fuel loads on Saturday.

Last year they had four laps in an often hectic one-hour qualifying session on Saturday with refuelling allowed between Saturday afternoon and the race.

The German's low point was a 17th-place start in Malaysia in March, while Montoya qualified eighth but since then he has been ahead of the Colombian 7-1 after Williams resolved aerodynamic problems with the FW25 car.

Williams technical director Patrick Head has his own theory for the sudden turnaround in his drivers' form: Montoya can wring more out of a wayward car but Ralf's greater experience allows him to get more out of a good one.

"People have said to me after qualifying 'why is it that Juan had so many poles last year and now Ralf seems to be a bit stronger?'" said Head.

"Just from my observation in the team, I think it's really just showing the different level of experience between Ralf and Juan in the car.

"Ralf seems to get his car closer to an optimum a bit quicker than Juan does during the practice sessions," he said at Magny-Cours when the team mates lined up first and second on the grid.

"I don't think it has got anything to do with the speed of the driver as such. I think it's just that difference in experience and application and knowing what to do during the practice."

While Ralf came into Formula One in 1997 with Jordan, Montoya arrived in 2001.

QUICK HANDS

Head said that anyone who had watched the former Indianapolis 500 winner and CART champion on American oval circuits would realise that the Colombian had phenomenally quick hand reaction and responses to wayward behaviour of the back end of the car.

"On one lap qualifying, if he's got a difficult car, it's possible that Juan will make a better job of that than Ralf," said the Briton.

"The car now, no way is it easy to drive but it's clearly more stable. We can see from the actual amount of steering movement in the car that it's a lot more stable than our car was last year.

"So it probably requires less sudden correction and in that situation maybe Ralf is able to go a bit closer to the limit than Juan."

The positive for Montoya is that at least he has won a race this year, and the glamorous Monaco Grand Prix to boot, whereas last year he drew a blank on raceday.

He is also still in the title reckoning, six points behind Ralf and 17 adrift of Ferrari's Michael Schumacher with six races remaining.

The Colombian has said he fears Williams could get a wake up call at Silverstone on Sunday, with rivals Ferrari and McLaren generally going well there, but the track itself holds no surprises.

"The majority of teams spend a lot of time testing at Silverstone so most of the drivers could drive the track blindfolded," he said.