Let me try to explain that a bit better, on the offchance that anyone is interested:
If I work in the city earning 100k. I pay tax at 40% on any earnings above about 40k.
However, if I buy a second home in the country, I set it up as a business. A loss-making business. Let's say that the mortgage costs 20k per annum, with further allowable expenses of 5k (gardener, cleaning, etc).
I advertise it for let on the internet, for certain weeks of the year. Say this generates 10k of income.
I then fill in my tax forms stating that I have made a 15k loss on the investment for that financial year. If I play my cards right I can offset this loss against gains made on other investments/paying work. Meaning I effectively get a subsidy of 40% from the taxpayer towards my 'nest egg' of a second home.
In say 20 years, when the mortgage is paid off fully, I no longer need this loophole. I have paid off my asset in full.
If I want to sell it and avoid capital gains tax, all I need to do is to claim it is my main residence (easier to do if retired already, say at 55).
Bingo, a no-brainer investment scheme.