BUDAPEST, Aug 2 (Reuters) - McLaren gagged Lewis Hamilton and Fernando Alonso at the Hungarian Grand Prix on Thursday to shield them from a spy controversy surrounding the Formula One leaders.

Double world champion Alonso was withdrawn, with the permission of the governing body, from the scheduled International Automobile Federation (FIA) news conference at the Hungaroring.

Hamilton's regular sessions with reporters were also cancelled, although the championship leading rookie went ahead with an engagement for title sponsor Vodafone in Budapest in the morning.

With team chief Ron Dennis not arriving at the circuit until Friday, the team wanted to keep the drivers out of the firing line.

McLaren, 27 points clear of Ferrari in the championship, published a long and hard-hitting letter on Wednesday in response to the Italian team's allegations about their involvement in the controversy gripping the sport.

Uncertainty still hangs over the Mercedes-powered team's title prospects, despite an FIA hearing last week which decided not to impose any penalty on them for unauthorised possession of Ferrari information.

If the appeal court were to overturn the World Motor Sport Council verdict, McLaren could face sanctions ranging from a reprimand to exclusion from the championship.

The initial verdict triggered fury at Ferrari, who maintain that McLaren have gained from significant leaks of information.

McLaren deny that and have accused Ferrari of running a car with an illegal floor device at the season-opening Australian Grand Prix.

Questions about the 'spy saga' were off-limits at the sponsor event but Hamilton spoke of the title battle with Alonso, who is two points behind with seven races remaining.

"For sure I have Fernando breathing heavily down my neck, but that is not too much of a worry," said the 22-year-old.

"Going into this race we have a great car, a great team, and I feel we can perform like we have all season," added the Briton, whose run of nine podium finishes in a row ended with ninth place at the Nuerburgring.

"The last race was an eventful one. So it will be good to come here and get back on form."

"But I really came away from the last race with a smile on my face. Yes, I lost 10 points, but I learned so much as to when I should switch to wet tyres or dry tyres.

"I also reminded myself in the race that you never give up. I had a puncture, I went into the gravel, I got stuck behind the safety car, I chose the wrong tyres, lots of different things happened in that race, but I kept on pushing to the end.

"So it was a good stepping stone for me, to prove to myself that never giving up is the key."