Almost 160,000 vehicles were built last month, an increase of 0.9% compared with last September, with exports topping 120,000.
The export figure was 5% higher than a year ago, compared with a 10% decline in production for the home market. The new numbers follow a report yesterday from car dealer Pendragon which predicts UK car prices are to remain steady.
Similarly, export growth is keeping production of commercial vehicles steady, despite a fall in domestic demand. Last month, 9,742 commercial vehicles were built, little-changed on the 9,811 built in September 2015.
But while domestic sales of 4,020 marked an 18% plunge on September last year, export business was 16.5% higher at 5,722.
Figure are from the trade body, the Society of Motor Manufacturers and Traders (SMMT), which said car production for global markets had increased for 14 months in a row.
Just over a million cars have been built for export so far this year, the highest since records began in 1995. The figure for commercial vehicles is 36,696.
Mike Hawes, SMMT chief executive, said: "British-built cars are in demand across the world as demonstrated by the double-digit growth in exports this year, resulting in more than a million cars produced for international markets.
"The vast majority of cars manufactured here in the UK are destined for abroad and future growth will depend on securing our international competitiveness and the barrier-free access to major global markets that has enabled the UK automotive industry to thrive."
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He added that the commercial vehicle sector “is broadly stable, with output remaining at a high level.”
Exports of all kinds have been helped by the decline in sterling’s value, which makes British goods more competitive in foreign markets.
Greg Clark, the Business Secretary, said: "The UK automotive sector has had a remarkable year, exporting over one million cars all around the world.
"This is thanks to our highly-skilled workforce, the strong partnership between Government and industry and long-term investment in new technology and innovation.
"The Government is committed to supporting this industry and that is why I was in Japan last week meeting automotive sector representatives and making clear the UK remains open for business."