British manufacturers' order books slipped in September, as export business weakened with little more than six months to go before Brexit, according to the Confederation of British Industry.

Its monthly factory orders balance fell to a four-month low of -1 from +7 in August, although it remained above the series' long-run average.

"While manufacturing order books remain strong and output is still growing, Brexit uncertainty continues to cloud the outlook," CBI head of economic intelligence Anna Leach said.

"Heightened fears of a 'no deal' Brexit scenario have prompted some firms to move publicly from contingency planning to action."