Hi Folks

Can anyone help me please. I have recently purchased a 2003 Ford Mondeo Zetec S Estate 2.5 V6 and the vehicle came without a spare wheel, but curiosly came with the jack, wheel brace etc. Can some one tell me if the spare wheel should be a full size wheel or a space saver and what the size should be? The car is sat on 18" rims at the moment.