What can potentially make a Will invalid?

There are various reasons that a Will could be argued to be invalid and I will try to explain this in more detail here.

Capacity

A “testator” (the person making the Will) must have had sufficient capacity when making the Will , otherwise it could be invalid. They would have to be over 18 when making the Will, and have enough mental capacity to be able to understand what they own and the fact that their beneficiaries will eventually receive their estate. They must be able to appreciate the implications/consequences of including certain beneficiaries. They should be able to make these decisions free of any pressure from other individuals.

A fairly usual argument raised in a dispute, after someone dies if they were elderly, is that they may have lacked mental capacity when they made their Will. Just because someone was older when died, this does not automatically mean they lacked mental capacity, of course. 

Undue influence

A Will must be made free of undue influence, pressure or persuasion by others. Another argument that can come up during disputes over Wills is that someone was pressured into having their Will prepared in a certain way. Such an argument is sometimes used in cases where one child has been preferred by a Testator over others and was also perhaps actively involved in arrangements for the Will to be made, which could potentially then be seen to be to their advantage.

Forgery

Obviously, if a will is proven to be a forgery, whereby the signature was not actually given by the Testator it will be invalid.

A Will must be validly signed

For a Will to be valid, it will normally be in writing and will be signed in the presence of two independent witnesses (not beneficiaries or related to beneficiaries or the Testator) who must have mental capacity themselves. The Will should be signed first by the person making the Will and then by the two witnesses.

I have previosuly dealt with a case where a Testator made a Codicil to his Will and then died. This is a document that has the same signing formailities as a Will, and generally seeks to alter certain parts of a Will that is already in place. During the course of the administration of his estate, it transpired that the Codicil had not been signed in the presence of the two witnesses at the same time, as the Testator had in fact visited two seperate neighbours at differet times for them to add their signatures to the Codicil. As such, the Codicil was invalid which had fairly disastrous consequences for one family member. This shows that is generally a good idea to take proper legal advice when making changes to a Will.   

What else could make the Will invalid?

A will could be “revoked“ and be of no further effect if the Testator destroys it, or for example, remarries (remarriage generally always revokes a Will).