A German inventor has claimed to have made the world's most sophisticated sex doll.

Michael Harriman from Nuremburg, and aircraft mechanic, has developed sex androids that have 'hearts' that beat harder during sex. They also breathe harder and have internal heaters that allow their body temperature to rise. But, in order to imitate real life, their feet will stay cold.

"They are almost impossible to distinguish from the real thing, but I am still developing improvements and I will only be happy when what I have is better than the real thing" said Harriman.The dolls are priced at £4 000 each for the basic model, and extra charges appl;y for adaptations like larger breasts.

Underneath the doll's silicon skin, which has been developed for use in medical surgery, is an electronic heart that beats faster during the deed.The doll can also be made to move by remote control. With just the touch of a button she can wiggle her hips under the sheets and also make other suggestive movements.Harriman has stated that his design is an improvement on the popular 'real dolls' that are sold in the US.