Will I automatically get 4G on my new iPhone?

I'm currently using an iPhone 4s on a contract which has around 10 months left but have bought an iPhone 5. When I put my sim card in the iPhone 5, will I automatically get 4G or do I need to contact EE? FYI, I'm on EE at the moment.

No if your phone is LTE capible your sim would automaticly go on the fastest network availible in your area supported by your device if you have LTE/4G in the area you should get it

Yes, you'll automatically get 4G LTE if it's available in your area.