Five van makers and numerous major truck makers have said they will not exhibit at the 2009 Commercial Vehicle Show.
Vauxhall, Renault, Mercedes-Benz, Iveco and Isuzu have all withdrawn from the event, at Birmingham NEC in April, due to financial constraints.
Nevertheless, the show will go on, insist its organisers, which include the SMMT.
Nissan, Citroen, Ford, Fiat, Renault and Peugeot have committed to displaying their van ranges there.
In 2008 more than 28,000 visitors attended the show, which incorporated the Aftermarket Show for the motor repair sector.