i am appling for a job here in the uk and it the application form states that i need to bring proof of eligibility to work, what could this be? i dont have a passport but i do have a provisional driving license woud this work? thanks x
They need to be sure of two things:

a) you are old enough to be employed for the job advertised. i.e. over school leaving age or over 18.
b) you can legally work in the UK.

For a) bring Birth certificate or Driving Licence. Both carry your date of birth.

for b) if you have a British Birth Certificate that will cover that. Also bring your National Insurance No with you.

Take no notice of the idiot knocking you for having trouble with the application form, we all have to learn these things as we go along. Report him for spamming, I have.
In the US we have a state Id or state drivers liscence, to get that liscense we have to show our birth certificate, didnt you to get your provisional?
Also in the US we have a social security card, its got the number that our taxes are affiliated with, does the UK do this?
If you are a citizen of the UK then you are legal to work there, in the US we only have to bring the social security card and state id or liscence with us, other options listed on our employment forms are for persons here on a visa or whatever.
i dont think a provisional license would work. they are looking for things more like birth certificates and such.