Formula 1's intense heat on Pirelli reached boiling point at the 2013 British Grand Prix, due to shards of exploding tyre rubber at the Silverstone circuit. Mercedes driver Lewis Hamilton, just one of four drivers who had spectacular rear failures during the Silverstone race, was comfortably leading when he suffered a tyre blow-out.Hamilton commented: "They (Pirelli) need to do something. It's unacceptable" ‘WASTE OF TIME TALKING TO THE IAFRace winner Nico Rosberg had a partial tyre failure just as a safety car period began during the first 20 laps.Footage from Lotus’ Kimi Raikkonen and Ferrari’s Fernando Alonso showed how the big chunks of flying tyre debris could have hurt a driver.Hamilton said: "It's only when someone gets hurt that someone will be doing something about it. I think it's a waste of time talking to the IAF, and if they don't do anything that says a lot about them."McLaren managing director Jonathan Neale, whose driver Sergio Perez suffered one of the exploding tyre failures, insisted: "We have to make sure our drivers are safe."McLaren’s Jenson Button agreed: "The cars behind get hit by rubber that has metal in it. It's obvious it's got to change. It's very scary."Pirelli said it wanted to make a fundamental change to the tyre construction, replacing an internal steel band with a kevlar one, to stop delaminations. It seems teams such as Lotus blocked the move.F1's official tyre supplier instead had to tackle the issue by deploying a new kind of glue to bind the tread.NO ANSWERS FROM PIRELLIAll the talk immediately after the race on June 30 was about the obvious need for Pirelli to change the tyre construction, whether or not the teams agree.Pirelli's Paul Hembery refused to immediately comment pending an investigation, despite the international media relentlessly bombarding him with questions.Hembery said: "Sorry, when we have the answers, we'll let you know."Meanwhile, a gearbox failure for Sebastian Vettel means the Red Bull driver's points lead over Fernando Alonso was slashed from 36 to just 21 points.