From Mr Colin P. Fenton.

Sir, Nick Butler (“The low oil price calls for a fresh set of rules”, December 16) should not go unchallenged. Contrary to his claim that there were no oil supply surprises in 2008, a short review includes: the first decline in Russian production in a decade, shocking delays in the start-up of Saudi Arabia's Khursaniyah field, 14 per cent of Gulf of Mexico production still shut in due to Hurricane Ike, the first-ever raid on a deepwater facility (the attack on Bonga, 120 miles offshore, by the Movement for the Emancipation of the Niger Delta), the August bombing of the Baku-Tbilisi-Ceyhan pipeline (which forced a 480,000 barrels per day drop in Azeri production) and, in another first of its kind, Somali pirates’ capture of a Saudi supertanker.