A combat deployment for the ship took place in 2001 . A large British exercise , Saif Sareea II took place in Oman in late 2001 . During the exercise , the terrorist attacks on the World Trade Center took place . '' Illustrious '' remained in theatre while other elements of the task force returned to the United Kingdom . '' Illustrious '' had elements of the Royal Marines on board , ready for possible combat operations in Afghanistan . No deployment was made before '' Illustrious '' was relieved by '' Ocean '' in early 2002 and returned to Portsmouth after seven months at sea
terrorist attacks
September 11 attacks
HMS Illustrious (R06)