Got asked this today by colleague, this is his first year renting out a property (since apr '08), and he made a loss on the rent vs mort. interest and so didnt think he had to make a tax return.
Just from frequenting here a lot I thought he had to make some sort of a return even if he did make a loss
He should definately make a return. He can offset the loss against any future gains to reduce his tax bill in a year he makes a profit. He should also make a return of rental income against all costs not just mortgage interest.