Registrations of new buses and coaches fell by 15.3% in the second quarter of 2017, according to the Society of Motor Manufacturers and Traders (SMMT).
It is the second consecutive fall, following five previous periods of growth, mainly due to lower orders with the deadline for PSVAR compliance being met.
Year-to-date figures show a similar pattern, with registrations of buses and coaches down 10.4% and double-deck demand down 6.1%.
Detailed figures of registration by manufacturers are no longer published by the SMMT.
The trade body says that double-decks declined by more than a third (36.9%) in the quarter, while single-decks saw a moderate rise of 4.7%, with volumes in line with annual trends.
In total 3,982 minibuses, coaches and buses were registered during January-June 2017, compared with 4,445 in 2016
