Hi there. I think you would really need to make enquiries at specific universities to see what is acceptable in your field. In very competitive subject areas you would need at least a 2.1 and a masters (preferably a first and a distinction at masters for the best chance of funding), but in a lot of other fields it is a lot less tough. A friend of mine in economics got a fully funded PhD with a 2.2 and a pass at masters, so you can see how much entry requirements vary according to subject. I don't know much about engineering, but I don't think it is too competitive compared to some other topics. I would imagine that with a 2.2 you would at least need a masters degree, but best to speak to a few departments you are interested in applying to and find out. Good luck, KB.