Mr Denli, a specialist in chassis design, was appointed to lead the engineering team working on the car's front suspension and chassis from September 2022, halfway through a design and testing phase he says had an unusually tight timetable.
He soon became concerned VinFast was cutting corners with safety, keeping costs down by employing a small team of inexperienced engineers.
His concerns grew when he heard three of his predecessors had quit after short spells on the project.
He says in February and March 2023, while running vigorous testing on VinFast cars at the Mira Technology Park near Nuneaton, two components snapped off and another two failed.
He reported the "extremely concerning" incidents to colleagues at Tata Technologies Limited (TTL), the consultancy's UK division, based in Leamington Spa, Warwickshire.
In subsequent testing, he alleges further components failed.
Mr Denli said they were failing after fewer than 25,000 km (15,534 miles), when normally they would be expected to last for at least 150,000 km (93,205 miles).
"In the drive units, some of the brackets were completely failing and falling out on to the road," he said. "We're talking one or two kilograms worth of aluminium.
"These [incidents] started causing alarm bells to go off just a short time before we we went into production."