Idont know if they work or not? alot of companies make you pay to unlock the phone on pay as u go, whilst others will unlock it if you have spent enough money. Or you could go to free vouchers and codes and type in you are looking for free sim cards for tescos orange o2 vodafone and many more free sims. i have seen loads of free sims on my travels.. or maybe just type tescos free sims in your search box. im sure you will find one . good luck i hope this has been of some help.. worth a try. as i said i have had free tesco sims and many others of the web x ps o2 are giving away sims with 1000 mins on at the moment.