The owner of British Gas, Centrica, has blamed “normalising” market conditions after two years of bumper results for its heavy slide in profit in the first half of this year. Centrica—the FTSE 100 constituent that owns British Gas and looks after Scottish Gas and Bord Gáis—reported a near 50 percent decline in adjusted operating profit for the six months to 30th June, from £2.1bn to £1bn. Basic earnings per share dropped from 25.8p to 12.8p, and its free cash flow fell from £1,377m to £816m.…