Lord Drayson, a former Rover car worker who went on to become a millionaire businessman, sparked a storm of controversy yesterday after quitting the Government to pursue his motor racing dream.

Downing Street announced yesterday morning that the Aston University graduate was taking "leave of absence" from his post as Defence Equipment Minister to take part in the American Le Mans motor racing series.

The announcement came just a few hours before a coroner criticised the "chaotic" military supply chain after hearing how a 19 year-old soldier died in a roadside bombing in Iraq. Oxford coroner Selena Lynch said vital bomb-disabling equipment which could have prevented the device from detonating and killing Fusilier Gordon Gentle was not supplied to his regiment.

After the inquest, Fusilier Gentle's mother, Rose, criticised Lord Drayson's decision as insensitive timing.

The peer, who lives in Stroud, Gloucestershire, was praised by Defence Secretary Des Browne for having "worked tirelessly for over two years to improve the way in which we equip our forces".

But shadow Defence Secretary Liam Fox said: "The only Minister with any credibility in the defence industry has now abandoned ship.

"This will cause concern throughout Britain's vital defence industry.

"At a crucial time for major procurement programmes such as Joint Strike Fighter and the Carrier project, with the resulting impact they will have on British defence jobs, there will now be no one with any defence industrial experience within the Ministry of Defence's ministerial team."

Lord Drayson of Kensington - born Paul Rudd Drayson - graduated from Aston University in 1982 with a degree in production engineering.

He first hit the headlines in the aftermath of the September 11 attacks when his company won a £32 million Government contract to supply smallpox vaccines.

And his life peerage in 2004 from former Prime Minister Tony Blair came within weeks of a £505,000 donation to the Labour Party.