»Museum recreated breath of a T-Rex«

Re-creating the breath of a T-Rex for a huge model dinosaur in London's Natural History Museum posed challenges all of their own.

"We spoke to palaeontologists, who gave us a description of the dinosaur. Basically the bigger the creature the smellier they were," said Knight, who is passionate about accuracy.

"The dinosaurs would have had open sores from fighting, and rotting meat stuck in the gaps between their teeth.

"We needed all these features in the eventual odor," he said.

T-Rex breath turned out so accurate and so revolting, the curators instead opted for a milder swamp smell to evoke the creature's natural habitat.

Requests for nasty smells come in quite a lot, requiring some unpleasant research.

"I've had otter poo on my desk," said Knight, who created the odor for a zoo's nature trail, alongside the smell of jaguar urine and rotting flesh.

Some jobs are easier on the nose. Dale Air has supplied branches of British travel agent chain Lunn Poly with the scent of coconut oil, aimed at increasing the time customers spend in their stores.

Dale Air started life as an air-freshener firm. Then founder Fred Dale, who died earlier this year, found a lucrative sideline.