Complex sentence: Before this, they had endured a "hostile" and highly controversial tour of Pakistan, during which an argument between captain Mike Gatting and umpire Shakoor Rana had led to a diplomatic incident.
Split into simpler sentences: Before this, they had endured a "hostile" tour of Pakistan, which had been highly controversial. An argument between captain Mike Gatting and umpire Shakoor Rana led to a diplomatic incident.