In the UK, Ofcom (the telecom regulatory) rules stipulate that network carriers can no longer sell locked devices to customers. If you have a locked device and wish to join Slice, follow these steps:

1. Contact your carrier and request an unlock code. Also, request the steps required to use the code on your device.

2. Gather the right information needed to unlock e.g. the carrier may ask for account details or proof of purchase.

3. Wait until the unlocking is complete - it usually takes less than a day.

Once you have unlocked your device, you'll be free to use any eSIM on that device going forward.