Paul Drayson, the Labour donor whose vaccine company has received two lucrative contracts, calls himself "doctor". His PhD is in robotics from Aston University in Birmingham, and his background is strictly entrepreneurial. He worked for Rover cars, and then made his first money developing a technology to create snack biscuits in fancy shapes.

After a management buy-out from Trebor netted him £250,000, Drayson turned his energies to medical engineering. His Oxford-based Powderject company, with a family share estimated at £100m, was set up to develop a revolutionary needle-free injection system through the skin.

But Drayson makes most of his money from acquiring relatively old-fashioned vaccine companies. The heart of his operation is Evans Vaccines, a factory in Speke, Liverpool. He sells Fluvirin, a flu vaccine.

Last year he moved into profit for the first time. The reason was simple. Ministers at the Department of Health awarded him a contract to sell them TB vaccines at a rate four times higher than previously. Drayson won a £17m, two-year deal. But ministers are now looking to Danish firms in the hope of renewing the contract at a cheaper rate.

Two months after getting his contract Drayson wrote a letter to the Financial Times praising Labour science policy, and followed it up with a personal donation of £50,000. Labour declared the cash.