The only way to know for sure is to apply @Jakeavery , but if you know you have poor credit then chances are it will get declined.
What you might be able to do as a half way step is move to a SIM only deal. The reason for this is that normally, so long as your payments are made on time and without issue, you can upgrade from that to a phone contract and are more likely to get approved.
See this thread for someone doing just that:
https://community.o2.co.uk/t5/Pay-Monthly/Sim-only-upgrade-changed-from-3-6-months/m-p/1570027
Please note, this is not customer services and we cannot access your account. Do not publish personal details (email, phone number, bank account).
Link to our guide on how to contact them can be found here
