Advice on SIM card?

The wife has upgraded her phone, and now I have her iPhone 4s.
I have my work phone which I have had for over 10yrs and have never changed the sim. I have used the sim on various android phones and it works fine, as long as I unlocked the phone.
Can I cut down the sim to fit the iPhone and will it work? The sim is a vodaphone and the wife had her contract with orange.
Cheers