Four of the smallest ships in the Royal Navy are preparing to head far north into the Arctic and take part in a major exercise that the fleet's largest ship, HMS Queen Elizabeth, has been forced to pull out of because of a propeller "issue".The departure of the fleet flagship from Portsmouth Naval Base at the weekend was cancelled at the last minute after final inspections spotted a problem with the starboard propeller coupling.The £3.5 billion warship had been heading out to lead Exercise Stead

Four of the smallest ships in the Royal Navy are preparing to head far north into the Arctic and take part in a major exercise that the fleet's largest ship, HMS Queen Elizabeth, has been forced to pull out of because of a propeller "issue".The departure of the fleet flagship from Portsmouth Naval Base at the weekend was cancelled at the last minute after final inspections spotted a problem with the starboard propeller coupling.The £3.5 billion warship had been heading out to lead Exercise Steadfast Defender - the largest Nato exercise since the Cold War - which will take place off Norway's Arctic coast in March.