In order for a will to be considered valid, the testator (i.e. the person making the will) must have sufficient mental capacity at the time of making or altering their will.

The problem is, the term ‘mental capacity’ can often be challenged. In a recent case, and father disinherited his daughter and left his entire estate to charity a few weeks before committing suicide.

The court found in favour of the charity on the basis that the testator had the necessary mental capacity to write out the will.

Such disputes can hinge on what is known as ‘testamentary capacity, i.e., whether the testator was of sound mind at the time and date of writing or altering the will.

If it is deemed that the testator (the person making the will) does not have the required mental capacity at the time of writing or altering the will, then the will can be considered invalid.