Gas and electricity provider Centrica said it put in a resilient performance in challenging conditions in 2011.Revenue edged up to £22.8bn from £22.4bn in 2010, ahead of market expectations of £21.9bn. The British Gas owner, which has been buying up its own energy producing assets of late to ensure a source of supply, saw underlying profit before tax of £2.06bn, versus expectations of £2.17bn. Exceptional items, however, put a £794m dent in those profits, reducing them to £1.27bn, down from 2010's £2.81bn; the 2010 figures benefited from exceptional credits of £880m. The full year dividend has been bumped up by 8% to 15.4p from 14.3p in 2010.More to follow ...jh