DO YOU remember Doctor Who's annoying pet dog K-9? Back in the 1970s, the concept of a robotic dog was the stuff of science fiction. Today it's science fact.

Earlier this year Sony decided to flex its corporate muscle to produce the world's first fully working example of a robotic pet.

The result was called Aibo (pronounced eye-bo). Only a limited number was produced and the price was eye-watering, but Aibo was so impressive it sold out almost overnight. Those first robot dogs are now prized collectors' items.

Pleasantly surprised by Aibo's success, Sony formed a new off-shoot - Sony Entertainment Robot Company - to develop the concept.

The result is about to hit the shops just in time for Christmas.

Aibo 2, takes the concept of a robot dog several steps further yet, thanks to the larger production run, it costs considerably less than the first version. Externally, the new robot has moveable ears and a shorter tail.

A microphone in the robot's head helps the dog respond to your voice. Give him a name and he'll remember it. Call his name out and his ears will prick up, his tail will wag and he may even come to you, depending on his mood, just like a real animal. Each Aibo can be taught a maximum of 40 words - about the same as a real dog.

When you unwrap an Aibo on Christmas Day and switch him on for the first time, he's nothing more than a whimpering pup. It's your job to train him and help turn him into a well-rounded pet.

Just like a real pup, he'll demand attention, and stroking him (there are three sensors on his head, back and chin) makes him happy. If he performs a trick (or chases his pink ball around the room) and you are happy with him, then tickle one of the sensors and he is more likely to do it again.

This is no mere gimmick, either. Aibo is a sophisticated computer and how you train him really does have a bearing on what sort of robo-dog you get. Give him too many strokes and he'll become lazy and indulgent. Rule with a rod of iron and he'll cower away from you, hiding when you walk into the room.

Other innovations include a digital camera inside his head. Say "take a picture" and he'll snap away. These are stored on the memory stick for downloading to a PC - you can build up a library of the world seen from your pet's eyes.

Unfortunately, he will cost you money. Lots of it. Even a basic Aibo will ring the till at £1,000 and deluxe variations are even more.

But that's missing the point. Aibo is no toy. The shops are filled with cheap copies costing less than £100 but they can't do a tenth of the things Aibo is capable of. They will only ever be entertaining toys.

Aibo, on the other hand, marks the beginning of a whole new generation. In 30 years time, when we've all got ultra-realistic electronic pets, no doubt he'll seem hopelessly quaint, but for now he is the ultimate in household robots.