Cargo to and from emerging markets at London Heathrow increased 1.8% over the past 12 months, said the airport authority. Traffic with Mexico was up 31%, Turkey 27% and China 3%.

The airport said this underlied the export growth potential of an expanded Heathrow which would be able to offer up to 40 new long-haul connections. The issue of airport expansion is proving controversial, after the Government announced in mid-December yet another delay on whether, and how, to expand runway capacity in the south-east of England.

Several business organisations, including British Chambers of Commerce, London First and the Unite trade union have written to the Prime Minister saying that it was fundamental to securing the UK’s long-term growth.

Heathrow’s overall cargo traffic was quite flat, showing a 3.1% decline in November 2015 compared with November 2014. The first 11 months of 2015 was 3.1% down on the same period of 2014, while for the 12 months to November 2015 it nudged up by just 0.3% to 1.496 million tonnes.

Gatwick could be one beneficiary if the UK government decides not to press ahead with a third runway at Heathrow; the UK’s second gateway has been pressing to be allowed to build a second runway.

However, Gatwick’s own cargo traffic was 11.2% down in November, and fell by 16.4% to 74,247 tonnes in the 12 months to mid-November.