The key facts about ICC ranking are as follows. The ICC World Test Championship rankings are a system used to rank teams in the ICC World Test Championship. According to the provided evidence, England’s Harry Brook has become the No.1 batter in the rankings. However, the evidence does not provide information on the current rankings of teams or the criteria used to determine the rankings. It also does not specify how the No.1 batter is determined or what the current ranking of Harry Brook is in terms of points or position. The evidence only mentions Harry Brook’s achievement of becoming the No.1 batter in the rankings. The ICC World Test Championship rankings are likely based on a team’s or player’s performance in Test matches, but the specific details of the ranking system are not provided in the evidence.