PARIS (Reuters) - European stocks ended at their lowest close in 1-1/2 years on Wednesday, as investors' relief following a surprise hefty U.S. interest rate cut quickly vanished and fears of more mortgage-related writedowns hit banks again.

Shares of energy companies were among the biggest laggards, sinking along with crude oil prices on persistent worries over a U.S. recession. Royal Dutch Shell (RDSa.L: Quote, Profile, Research) shed 4.8 percent, Total (TOTF.PA: Quote, Profile, Research) fell 5.8 percent and Repsol (REP.MC: Quote, Profile, Research) lost 3.2 percent.

The FTSEurofirst 300 index of top European shares unofficially closed down 2.8 percent at 1,267.80 points, after falling more than 4 percent during the session.

"The big burning question is whether the Fed has done enough to stem the negative tide on the credit crisis, the housing market downturn and the risk of recession. Judging by the stock and credit markets response so far, they need to fill the gap some more," Bear Stearns analysts wrote in a note

(Reporting by Blaise Robinson)