Explanation: The meaning of "made it impossible to contemplate an Eastern fleet" refers to the fact that due to the damage sustained by three British battleships during the attack on Crete, it was no longer possible for the British to consider forming an Eastern Fleet. The attack on Crete resulted in the British being unable to use those battleships, and thus their capacity to form an Eastern Fleet was severely limited. This made it impossible for the British to consider forming such a fleet at that time.