The Co-operative Group plans to overhaul its UK depots through the installation of wireless systems, mobile computers and voice terminals.

The society has signed a deal with technology company Zetes that will transform its warehouse and management systems, and includes voice-picking systems. The technology is already in place at The Co-operative Group's 350,000 sq ft centre in West Thurrock, but will now be rolled out through its nationwide distribution network.

A spokeswoman said the new installations were more sophisticated than previous systems, and would improve accuracy and productivity. But she refused to disclose the cost.

A Zetes spokesman said: "We work with the best hardware and software  manufacturers to offer the most appropriate solution for customers."