You should not assume that your spouse or civil partner will automatically inherit all your assets. As from 1 February 2009, under the rules of intestacy (death without a will) if you have children, your spouse or civil partner is only entitled to the first £250,000.00, the statutory legacy, and a life interest in half the remainder. If there are no children the entitlement increases to £450,000.00. It the estate is worth more than the statutory legacy the position is more complex.
If you die intestate, are married with children and your estate is worth more than £250,000.00, your spouse would, as outlined above, receive £250,000.00 and a life interest in half the remainder. On the death of the spouse or civil partner this would pass directly to the children. The children would receive the remainder of the estate when they reach the age of 18, however if any of your children predecease you then their share would be distributed amongst their own children (your grandchildren).