Its not a terrible idea, BUT it could go really wrong, so ou need to be really careful.
First, choose the right house - location, price, rentability, fairly maintenance free, hopefully in an up and coming area for added capital growth. These criteria may not match with the sort of house you personally want to live in.
You need to be absolutely sure what rent you can get. Dont just ask the agent selling you the house. Letting individual rooms is usually a better income, but is very hard work. So a small family house is generally better.
You would need to fix the mortgage rate until 2018, so you know exactly what thats going to cost you.
Then there's the rest of the costs: insurance (£200pa), management fees (10% of rent + VAT), gas safety (£100pa), maintenance (est 10% rent).
Certainly not for the faint hearted and you would need perosnal income to see you through probable tough months when its empty, or tenants dont pay, or the boiler breaks...