Lotus team boss Eric Boullier has hit out at Pirelli's decision to make changes to its F1 tyres in time for the Canadian Grand Prix next month.

The tyre supplier confirmed the move on the back of the Spanish Grand Prix, where Pirelli motorsport boss admitted that the number of pit stops carried out as drivers battled against degradation were 'too much.

The decision is likely to aid those teams who have struggled to come to terms with the 2013-spec tyres but could remove some of the advantage currently enjoyed by those - such as Lotus - who had found ways to master the rubber being provided this year.

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Speaking following the announcement of the changes, Boullier hit out at the move and said he was frustrated that some teams were being penalised for doing a better job.

"There aren't many sports where there are such fundamental changes to an essential ingredient part-way through a season," he said. "Just imagine for a moment that, because a football team can't run as fast as its opponent, the dimensions of the pitch are changed at half time!

"That there are changes to come can be seen as somewhat frustrating, and I hope they are not too extreme. It's clear that Pirelli have found themselves in a difficult situation and under pressure from different quarters. Last year, when we were designing our 2013 car, each team received information from Pirelli and everyone did the best job they could to develop a chassis which would make best use of the tyre characteristics. We even ran with some experimental 2013 tyres at the end of last season, to assist us in confirming our development paths.

"As with every season, some teams do a better job than others with their designs, and some drivers are more adaptable than others to the changes of both car and tyre. It is frustrating when you've developed a car from a set of tyre specifications which are available to everyone - for tyres that are the same for everyone - to then be told that they are being changed mid-season.

"That said, we have a team of talented designers and engineers who will be working twice as hard to ensure we adapt to these changes in the most competitive manner."