If you have been in the UK 2 years your international permit is not valid. (As they only last a year it will be out of date anyway - if you've got one with a longer validity it's a fake - widely sold in the USA)
If you are from the EU then your home licence may be valid - it's that you need to find. Even if it's not from the EU it would be useful to show you at least have a licence.
If ylou can't find any of them (and probably even if you do) you will be fined for driving without a (valid) licence