Spacesaver spare wheels. Legal when towing?

Rob2CathDavies

Hi! I have been unable to find a definitive answer to the question "Is it legal to tow if your car is using a spacesaver spare wheel?"  does anyone know? 

Also, can anyone tell me if any new towcars around £25k or less, come with a full size spare (apart from VW Passat and Kia Sportage which are the only two I can find).  Or at least space for a full size spare. 

thanks, anyone who can help!