A sizeable error has been found in official UK trade data, such that the third quarter external trade deficit did not narrow to £11bn from £12.7bn as first announced but in fact increased from £9.9bn to £17bn.

The Office for National Statistics said it had found a "processing error" in the exports and imports data's 'erratics' series, which includes non-monetary gold, silver, precious stones, aircraft and ships.

The £6bn ONS error in the trade deficit would have "no impact on total gross domestic product", the agency said, as the corrections to components of trade and the acquisitions excluding disposals of valuables had offset each other.

"The error does not affect any series before January 2015, nor does it affect the trade in services series. Corrections to trade data will be incorporated into the UK Trade release on 9 December 2016," the ONS said.

"Because the “erratics” series is volatile, a total trade series that excludes erratics may provide a better guide to the emerging trade picture. We will therefore include a total trade in goods and services excluding erratics series in the next release to supplement the trade in goods excluding erratics series already available."