(ShareCast News) - Centrica was the biggest faller on the FTSE 100 after an unplanned outage cut its North Morecambe gas sub-terminal output to zero on Tuesday.Centrica, the owner of British Gas, said gas production was cut off due to an "offshore issue".Flows from the Barrow terminal, which includes the North Morecambe sub-terminal, were running at around 1m cubic metres per day compared with 5.2 mcm delivered on Monday.At 11:27, Centrica shares were down 2% at 277.30p.