Lloyds Banking Group fell 2.4% after reporting Â£1.4bn more PPI provision.  BA owner IAG, shares turned south - down 1.7% - after an initial gain on a strong rise in profits.
Broadcaster ITV was the biggest gainer on the 100 list, up more than 2% after it said US broadcaster Liberty Global had increased its stake to almost 10%.
The benchmark FTSE 100 index was down 13.89 at at 6,654.98 points.
BG was another early riser that turned tail. Shares at midday were down almost 1%. Core earnings nearly halved in the second quarter thanks to weak oil prices.
Thomas Cook shares fell 5%. Poor results on Thursday revealed it took a Â£25m charge on lost earnings because of the Tunisian terrorist shootings.
Shares in InterContinental Hotels were 3.2% lower. The company dashed takeover hopes saying it was not in talks with rival Starwood Hotels.
On the currency markets, the pound fell 0.2% against the dollar to $1.5574 and was down 0.55% against the euro at â‚¬1.4193.
(Noon): The FTSE 100 begins Friday with falls in quiet end-of-week trading.