Stock prices in London closed lower on Thursday, as the price of oil surged as the conflict in the Middle East widened and unnerved investors, after Yemen's Houthis attacked two Saudi tankers. The FTSE 100 index closed down 77.80 points, 0.7%, at 10,639.17. The FTSE 250 ended down 299.30 points, 1.3%, at 23,627.33, and the AIM all-share closed down 6.32 points, 0.8%, at 768.76. The pound was lower at 1.3303 dollars on Thursday afternoon from 1.3377 dollars at the equities close on Wednesday. Brent oil topped 100 dollars a barrel on Thursday for the first time since May, after Yemen's Iran-backed Houthi rebels struck oil tankers in the Red Sea.