Donna Bradshaw replies:
The situation regarding tax is as follows:

(a) If you sell your share before either of you die then you will be liable to capital gains tax (CGT) on the gain (subject to the annual CGT exemption and other reliefs). CGT is changing on 6 April 2008 and, if you do sell, it could be advantageous to wait for the new rules to come into effect.

(b) If you pre-decease your brother, your share will form part of your estate and there will be no CGT to pay. It may, however, be liable to inheritance tax.

(c) If your brother dies before you, there will be no CGT to pay until you sell or gift your share of the property. There may, of course, be conditions attached to ownership and sale of the property that I don’t know about; however, these won’t affect CGT.