BUZZ-Centrica: top FTSE faller after outage at gas sub-terminal
** Centrica (LSE: CNA.L - news) shares down as much as 1.7 pct at 278.1 pence on unplanned outage at North Morecambe gas sub-terminal
** Stock biggest loser among bluechip FTSE 100 cos
** Co says flows have since restarted
** Co also battling pressures on cash-flow in low oil-price environment
** "As an absolute minimum, Centrica must target becoming the most cost efficient of the big six energy suppliers within 12 months," Jefferies analysts said, adding that co is likely to report significantly lower H1 earnings (abhiram.nandakumar.thomsonreuters.com@reuters.net)