Coming up with a new idea for a computer game may not be a passport to the Millionaire's Club - but it can at least take you part of the way. The tired and slightly battered microcomputer software industry has spent much of this year waiting for the 'Next Big Thing'- with little sign of its arrival.

Until now, possibly. Though the software business is not the place to find it. The computer science department at Essex University, is. Amongst the artificial intelligence systems, natural language research projects and computer based training systems, there is a hot little item called Mud. Mud, stands for Multi- User Dungeons and dragons, and is a flash version of the Hobbit or Valhalla - a role playing adventure game. What's this got to do with 64 users? Quite simply that you are part of a privileged minority of computer users actually able to play it.

Mud is a major feature of the newly inaugurated Compunet service for 64 users. The only other Mud players around at the moment are those able to dial up the game running on Essex University's DEC system - an expensive business.

"The connection costs are the main barrier to getting more people playing Mud," commented Richard 'The Arch Wizard' Bartle, co-author of the game.

So what's it all about?

As the name suggests, Mud is a multi-player version of the adventure game Dungeons and Dragons. But once you get your teeth into it, it's far more combining the fascination of an adventure game with the spontaneity of on-line chatting as you meet other players in the game.

Mud also offers a much more sophisticated 'dungeon' than anything available on a micro at present. The program runs on a giant DEC System 10 super minicomputer and, according to Bartle, can handle as many as 40 players at once. "That is probably the limit with the game at its present size, but we can always make it bigger", Bartle observed. Like Valhalia and Hobbit, the game consists of a series of rooms in which treasure may or may not be hidden. Commands are fed through the network to the game and you can move about inside the dungeon in much the same way you might in any adventure game.

Where it comes into its own, however, is in its ability to allow players to talk to each other, form alliances, exchange items of treasure and, if you happen to be lucky, learn the secrets of the dungeon from other players.

The background to Mud is Essex University's extensive artificial intelligence research - the university is ranked second only to Edinburgh in the field. Bartle is involved in a project to look at artificial intelligence systems as applied to planning projects. "I was taken on at Essex under the University Grants Commission scheme to provide information technology lectures", said Bartle. But despite this academic background, Bartle is not slow to see the market for Mud. The commercial rights to the game have been grabbed by Century Publishing, the computer book publishers and through them the deal with Compunet has been negotiated.

The problem is, for the time being anyway, Mud playing is going to be expensive. Compunet is charging a £5 per month entry fee and the enormous sum of £3 per hour to play Mud on Compunet. This is probably cheaper than going through PSS to get to the Essex University Machine, but with the telephone charges as well, it is still going to be a costly business.

"We are considering rewriting the Mud system next year if we can get the finance to do it. This might make it more widely available" said Bartle.

When this happens, Mud is likely to become a big seller mainly because it is so addictive (ask the editor of Your 64 - he's a regular player).

One player in Wales became so obsessed with Mud that she played from midnight till dawn every night.

"When she received a £3000 phone bill for eight months, she had to stop," exclaimed Bartle.

So, if you join Compunet and are looking for a wholly different experience, it might be worth joining for a month to see what it's like.

According to Nick Green at Compunet, its version should be up and running by the time this hits the book stalls. Members just select it as an option through Compunet, when they will be transported through a gateway into the wonderful world of Mud. Green explained that the appropriate software to access Mud is stored at the main computer end and is loaded into your Commodore modem. For the technically minded it is a teletype emulator. Other microcomputer users will have to wait until someone else puts up an appropriate service - doesn't that make you feel smug?