UK engine manufacturing output declined 20.5% in February with 170,271 units built.
Production for domestic and overseas markets fell 13.1% and 25.9% respectively.
Engine output has fallen by a quarter so far in 2021, down to 338,562 units.
Mike Hawes, SMMT chief executive, said: ""Now one year into the coronavirus pandemic, UK engine manufacturers have seen their output significantly affected. With subdued car markets at home and abroad, new customs processes with the EU, and global supply chain issues impacting the sector, this month's figures are further evidence of the challenging circumstances. There is, thankfully, a roadmap out of the pandemic in this country but, with the majority of our engines exported, we need to see global markets on the road to recovery before UK manufacturers can look forward with confidence."