Disabling EDGE

[Guest spammyspam]

For my particular handset, where I get almost 24 hours of standby on GPRS, this figure is halved once I switch toe EDGE and even worse on any 3G connection. Since for me battery life is a priority over network speed, switching off WCDMA locks out the latter two, but I can't quite figure out how to disable EDGE.

Just to be clear I don't wish to disable data altogether, just the switching to EDGE mode. Any ideas?