Updates with closing prices

April 29 (Reuters) - British shares drifted lower on Wednesday as investors parsed a mixed bag of corporate earnings, with attention turning towards central bank decisions on both sides of the Atlantic.

The blue-chip FTSE 100 index .FTSE fell 1.2%, slipping for the seventh time in eight sessions and closing at its lowest in a month. The midcap FTSE 250 .FTMC eased 1%.

• AstraZeneca AZN.L and GSK GSK.L fell 1.5% and 5.4%, respectively, after both drugmakers stuck to their full-year forecasts despite posting better-than-expected quarterly profit.

• Lloyds Banking Group LLOY.L dipped 1.5% despite reporting a better-than-expected rise in first-quarter profit.

• Earnings season is in full swing with investors cautious of any impact stemming from the Iran war as surging oil prices continued to pressure markets. O/R

• Efforts to end the Iran war were at an impasse with U.S. President Donald Trump unhappy with the latest proposal from Tehran as he wants nuclear issues dealt with from the outset.

• The Federal Reserve was meeting later on Wednesday, followed by results from megacaps Alphabet GOOGL.O, Microsoft MSFT.O, Meta META.O and Amazon AMZN.O, which could set the tone for markets globally.

• With geopolitical uncertainty still high, the BoE was set to keep interest rates unchanged on Thursday.

• Tentative hopes of a resolution to the Iran war have helped steady the FTSE 100, putting it on track for a marginal April gain after the conflict drove its worst monthly slump in six years.

• Among other moves, DCC DCC.L surged 9.3% after the sales and marketing services provider said it was reviewing a cash takeover proposal from a consortium comprising U.S. investment firms Energy Capital Partners and KKR KKR.N.

• Money manager St. James's Place SJP.L fell 6% after reporting first-quarter net inflows of 1.53 billion pounds ($2.07 billion), down from 1.69 billion pounds ($2.28 billion) a year earlier.

($1 = 0.7407 pounds)