Aha, the first bit of Brown sleaze. The first of many I'm sure.
Apparently just before seizing No.10 in the Brown coup, he signed over his £700,000 pied-a-terre in London to Mrs. Brown. See the article in the Torygraph

Why would he do such a thing?
I have no problem with him owning a 700K flat, nor signing it over to his wife. It's his private business. But....
Apparently Sarah Brown has released equity in the flat with a mortgage, something many people do. However generally people do this either to raise cheaper finance as they intend to buy another property, or they intend to rent it out and repay the new mortgage from rental income.
If she rents out the property then she will surely take advantage of her personal tax allowance and the tax thresholds in order to reduce her tax bill as the rental income will be declared as personal income. Sarah apparently has no source of income, so she can use her full personal allowance and the banding up to 40%.

If the income was in Mr. Browns name, given we taxpayers are generous enough to pay him £180K, he would pay 40% of every pound of rental income in tax to his government.

So he screws us for every penny, yet potentially saves himself a few quid in tax through signing his flat to his wife. Let's see if gets rented out.....