Lotus is throwing open the doors of its factory this month, to celebrate 40 years of manufacturing at Hethel.The first-ever Lotus was built be founder Colin Chapman in 1948, but it wasn't until 1967 that the company moved to the former airfield in Norfolk that's been its base ever since.The site, 100 miles from London and 8 from Norwich, was purchased in 1966, when Chapman laid the foundation stone in the presence of racing driver Jim Clark.Since 1967, over 72,000 Lotuses have been built at Hethel.On 23 September, visitors will be able to take a tour of parts of the factory, including the assembly halls, and be driven around the test track."The event is a celebration of the Lotus brand, a thank you to all the Lotus enthusiasts around the world for their support over the years and a re-inforcement of our commitment to Norfolk and to the UK," said Lotus chief executive Mike Kimberley. "I would also like to personally thank all Lotus staff for their dedication and commitment over the past 40 years and for their help in commemorating this special day. Hethel is our headquarters and our home."Anyone arriving in a Lotus will be able to park on-site, while all other visitors will have to use a park and ride service.Tickets to the event cost £15 per car, for up to four adults. Under 16s get in for free.Visit the Lotus webstore or call 01953 608190, 608626, 608461 or 608348 for details.