You're talking now about people borrowing, to fund an investment on which they hope to make money? But they haven't set up a property company or investment company with filed accounts, and just pay personal tax?
Let's be fair about this.
Suppose as a private investor I borrow money to buy Premium Bonds, or shares in National Grid, or Krugerrands.
Should I be able to deduct the cost of the loan from my taxable profits and income?
Whatever rules apply to me should apply equally to Hawkeye when he borrows money to buy a bungalow and rent it out. And vice-versa.
Foreign property owners are already a scandal, and attempts have been made to treat them less generously.
Capital Gains Tax
http://www.wsj.com/articles/u-k-closes-a-tax-gap-for-foreign-owners-1423760946
https://wealth.barclays.com/en_gb/h...could-the-new-uk-property-tax-affect-you.html
Income Tax and an annual property tax
http://www.bkl.co.uk/how-we-can-help/sectors/property-and-real-estate/investing-in-uk-property/
Why are you dropping my name in there you thicko?