(Reuters) – London’s FTSE 100 rose on Wednesday, aided by gains in financial and mining stocks, while investors across the globe awaited the U.S. Federal Reserve’s policy decision due later in the day. The blue-chip FTSE 100 climbed 1.2% in early trade, with banks and base metal miners leading the gains, while the domestically focused mid-cap index advanced 1.6%. Base metal miners jumped 2.6% after hitting their lowest in nearly three weeks in the prior session, as metal prices rose.[MET/L] The Fed is expected to raise rates for the first time in three years later on Wednesday and give guidanc…