SILVERSTONE, England -A sharp piece of raised kerb on the inside of turn four of the Silverstone circuit was to blame for tyre failures which overshadowed the 2013 British Grand Prix.During a post-race inspection of the circuit at the Loop and Aintree corners, through which the cars drive before running onto the Wellington Straight, former Formula 1 technical director Gary Anderson identified a section of dangerous concrete that may have caused the punctures.‘WE SAW TYRES GETTING CUT’Anderson said: "We have heard a lot today about Turn Four and we have come to have a look at what could be causing these punctures."Looking at the part inside the kerb, it is green to match the grass, but it is actually concrete. The cars go over the section and the sidewall of the tyre could be getting caught on a sharp part of the kerb."It is about the height at which we saw the tyre getting cut and coming off."Both turns are to the left and see the cars ride the kerbs on their left side, a fact that explained why all of the tyre failures produced left-rear or in one case a left-front tyre blowout.Red Bull team chief Christian Horner said the race had been affected by the tyre fiasco.Horner said: "The issues with the tyres changed the complexion of the race so instructing the drivers to stay away from the kerbs changed the race."I think there will be some fairly serious questions being asked and I think Pirelli will address that. It's clear Pirelli need to do something, but the most important thing is that they address it."PIRELLI RESPONDSPirelli boss Paul Hembrey said: "The guys are going out to have a look now at Turn Four."It is one of the things we are trying to understand as we have not really see anything like it before. I am not going to blame the kerbing, but it can influence it, you have to understand all the factors involved."We will work hard now to understand all the facts. They are what count. What you have just shown us (the kerb at Turn Four) we have already started looking at."When we have the facts we will react and make sure we get to the bottom of what happened with those tyres."