LONDON, July 23 (Reuters) - Max Verstappen"s British Grand Prix collision with Lewis Hamilton cost Red Bull $1.8 million with "massive ramifications" for a team operating under Formula One"s budget cap, principal Christian Horner said on Friday. In a combative column on the Red Bull website, Horner revealed the championship leader"s seat was broken by the first lap impact in last Sunday"s race at Silverstone. He continued to blame Hamilton and said Mercedes" race winner and seven-times world champion had got off lightly with a 10-second penalty. "Given the severity of the incident and the lenient penalty, we are reviewing all data and have the right to request a review," said Horner. "We are therefore still looking at the evidence and considering all of our sporting options." Verstappen had started the race 33 points clear of Hamilton, after winning a Saturday sprint, but ended up only eight ahead after crashing out when they made contact at Copse Corner. Hamilton had tried to pass on the inside and Verstappen moved across, with the cars colliding. Horner complained to race director Michael Masi at the time about Hamilton"s driving and Mercedes boss Toto Wolff went to see the stewards before they had taken a decision, followed by the Red Bull principal. Masi had cleared Wolff to do so but teams have now been warned they face punishment in future if any personnel visited the stewards uninvited. Horner said he had gone to make the point that it was not appropriate for anyone to interfere and was pleased to see the FIA clarification. He defended Verstappen from accusations by Mercedes and Hamilton of being an "overly aggressive" driver. "You only have to look at the fact Max has zero penalty points on his licence and has not been found guilty of any on-track misjudgements in recent years," he said. "The aggressive 17-year-old F1 rookie Max Verstappen that Hamilton is referring to is not the Max Verstappen of today, just as Hamilton is not the same driver he was when he entered the sport. "The reality is that Hamilton has met his match in a car that is now competitive, and I agree that both drivers need to show each other respect, but Hamilton was the aggressor on Sunday." Horner said also that he was disappointed by the "level of celebrations" after the race by Hamilton and Mercedes, with Verstappen still in hospital for checks.