add this to /etc/wpa_supplicant/wpa_supplicant.conf
network = {
ssid="eduroam"
key_mgmt=WPA-EAP IEEE8021X
eap=PEAP
identity="#####@ucl.ac.uk"
anonymous_identity="anonymous@ucl.ac.uk"
password="#######"
priority=22357
proactive_key_caching=1
}
and change line in /etc/network/interfaces for wlan0 from wpa-conf to wpa-roam.