HMS Trafalgar (S107) is a decommissioned Trafalgar class submarine of the Royal Navy.
After Operation Veritas, the attack on Al-Qaeda and Taliban forces following the 9/11 attacks in the United States, Trafalgar entered Plymouth Sound flying the Jolly Roger on 1 March 2002. She was welcomed back by Admiral Sir Alan West, Commander-in-Chief of the fleet and it emerged she was the first Royal Navy submarine to launch tomahawk cruise missiles against Afghanistan.
In November 2002, Trafalgar ran aground close to Skye, causing £5 million worth of damage to her hull and injuring three sailors. She was travelling 50 metres below the surface at more than 14 knots when Lieutenant-Commander Tim Green, a student in the "Perisher" course for new submarine commanders, ordered a course change that took her onto the rocks at Fladda-chuain, a small but well-charted islet. Commander Robert Fancy, responsible for navigation, and Commander Ian McGhie, an instructor, both pleaded guilty at court-martial to contributing to the accident. On 9 March 2004 the court reprimanded both for negligence. Green was not prosecuted, but received an administrative censure.
In May 2008 it was reported that the crash was caused by the chart being used in the exercise being covered with tracing paper, to prevent students marking it.
She was not launched with a pump jet propulsion system, but with a conventional propeller, unlike the rest of the Trafalgar Class boats that followed.