Marks & Spencer is gambling on a combination of ATM and Token Ring networking technology, despite the failure of a similar initiative and warnings of service failures.

The network, covering up to 1,200 users, has been installed at Marks & Spencer Financial Services. The company, a Token Ring bastion, has installed ATM hubs and switches from IBM, which will interface with legacy Token Ring kit from different vendors.

The project, dubbed 'significant' by IBM, follows a similar undertaking for British Amercian Tobacco (BAT) to install an ATM-to-Token Ring network, which was shelved after six months.

BAT admitted it faced problems over source route bridging - the way in which devices on Token Ring networks let each other know where they are. This is a mechanism not naturally supported by ATM, which can create communication problems and cause devices to 'vanish' from the network.

Networking consultant Matthew Bell said: 'Marks & Spencer is going to have a lot of headaches.'

IBM, which beat Bay Networks, Cisco and 3Com to the contract, denied it had experienced source route bridging problems, but admitted the network could face difficulties because older devices offer 'significantly less' management statistics and slower throughput.

Marks & Spencer said: 'Our experts have done their research. I don't believe anyone will put in a system knowing there are serious flaws.'