The Caterham Seven
is based on the Lotus Seven Mark III - The Prisoner
drove the Mark IV, which had longer, more elaborate wings than the III.
The Seven is essentially an engine in a rectangular metal box, with four wheels poking from the sides and two seats attached to the back. In Superlight R form, the car has no doors, windscreen or hood, and can only be driven practically whilst wearing a motorcycle helmet.
Sevens appeal in many ways - they are relatively cheap, extremely simple, you can buy them in kit form, and they are reliable, in the sense that there isn't much to go wrong, and even if it does, you can fix it because you probably built the car yourself.
Self-assembly supposedly takes around 70 hours, and once complete, you have to arrange for a local garage - or Caterham themselves - to inspect the car for safety and emissions.
Below 100mph the Catherham Seven Superlight R500 is as fast as any roadgoing Ferrari; you would need to be a dedicated driver to exceed 100mph, however.
Sevens are built to race, or drive to racetracks; crash protection takes the form of extremely accurate steering and precise roadholding. Otherwise, the car does not feature ABS, EBD, four-wheel-drive, traction control, airbags, air conditioning, a sound system, leather, a boot, electric windows or vanity mirrors. Apart from direct competitor Westfield, only Morgan approach the same level of single-mindedness.