By Devik Jain and Amal S (Reuters) -London stock indexes fell on Thursday after the Bank of England raised interest rates by an expected quarter percentage point, while a profit warning by online fashion retailer ASOS hit the retail sector. The blue-chip FTSE 100 index and the domestically focussed mid-cap FTSE 250 index both ended 3.1% lower. The central bank raised rates to 1.25%, the highest since January 2009, and stuck to its more gradual approach as it warned that Britain’s economy would shrink in the April-June period. The 25-basis-point rate rise came against the backdrop of heightened…