What happens?
Any error messages?
Is the phone unlocked for use on any network?
If it is then it could be the stupid Apple/iPhone activation process that needs to (silently) send an SMS text message to a UK activation server and this will (silently) fail unless you have an active membership and some cash credit (e.g. €1) on your account to pay for the international/UK SMS message.
If this is the issue then you need to add €1 cash credit to your account then switch the phone off and on again and see if it starts working.
If you need to contact 48 support about this then see the links in my signature below.
