Jun.1 (GMM) The 2012 field is so even because the rules are so restrictive, according to Fernando Alonso.

Fernando Alonso, Scuderia Ferrari Photo by: xpb.cc

The Spaniard admitted to worrying about the "credibility" of the sport, in light of the common view that the tyres supplied by Pirelli this year are making winning and losing Grands Prix akin to a "lottery".

But Ferrari driver Alonso has another theory.

Asked by the Spanish news agency EFE why he thinks the championship is so closely contested, he said it is "partly because of the restrictions that occur each year in the rules".

"When someone discovers a double diffuser, the following year it is banned.

"When someone does the 'F-duct', the next year's it's banned. Last year there were the exhausts blowing into the diffuser, and this year they are gone," said Alonso at an event in Madrid.

"Every year there are more and more limits on creativity and the potential development of a car. We are seeing more and more similar cars, all the time (F1) becoming closer to GP2."

The 30-year-old insisted, however, that the cream always finds a way of rising to the top.

"Despite it being an incredibly tight championship, the first (placed) constructor is Red Bull, and then McLaren and Ferrari.

"And the first six or seven in the drivers' championship are the same names from last year," added Alonso.