So that's around £5000 a year, allowing for the rates, a bit of maintenance and the odd void month between tenants. What's the house worth? Even if you paid for it outright with savings, anything over £100,000 and it starts to look dodgy. Any borrowings and you're in bother.
It's been said before, but this whole game is based on capital appreciation, and a hope (or expectation) of future rent rises.