The comeback

Opec's deal is a seismic moment for the oil market. But forces beyond the group's control will decide how effective the cuts are

Kill the theories of Opec's demise. In one swoop on 30 November, the group has ended years of inaction, solved a raft of thorny internal problems and put itself back in the market's driving seat. Two years ago, on the eve of the fateful November 2014 meeting that would see Opec refuse to shore up a plunging market, a Saudi official said the kingdom was taking its "hands off the tiller". Now it wants the wheel back. The market has a new floor above $50 a barrel, and Opec will defend it. Call it the Falih Put. The deal on 30 November, coming just two months after the Algiers Opec meeting that promised action and eight years after the group last cut output, means the market now has a prop. Opec