By Sharon Kenchington
Boodle Hatfield solicitors
When a family member dies, emotions run high.
Not only is there shock and grief, but the discovery that you have been "cut out" of the Will is sometimes the last straw.
Where a financial inheritance is at stake and family members suspect foul play, a small grievance can easily escalate.
The situation is compounded by the existence of complicated extended families.
One or both parties to a marriage may have remarried following a divorce or be living with a new partner.
Often there is a second family of younger half-siblings or step-children and old rivalries can readily surface if someone is omitted from the Will.
An increasingly ageing and wealthy population also means a greater likelihood of vulnerable adults falling victim to unscrupulous family members or carers when making arrangements for the disposal of their assets after death.
Challenges might be raised in circumstances where money is divested away from the family to a "friend" of the deceased.
Remember the case of 88-year old widow, Golda Bechal, who left most of her £10m fortune to the Mans, owners of her favourite Chinese restaurant.
In this case, the significant estate was left to family friends instead of family members.
The High Court in London upheld the Will, which was being challenged, on the basis that a mild form of dementia did not necessarily mean that the testator did not understand the implications of making the Will.
Last year a court found that the Will ostensibly made by farmer Leonard Supple was a forgery.
The Will had left just £100 a year to his son with the remainder of his estate passing to an illegitimate daughter.
In other cases someone may unexpectedly leave the majority of his estate to a charity or other cause at the expense of family members.
The capacity to make a valid Will was contested in the case of Branislav Kostic, who left his £10m estate to the Conservative party, excluding his only son from benefiting from his estate.
The judge determined that the delusions which Mr Kostic suffered as a result of mental illness had influenced the decisions he had made about his Will and found in favour of his son.
Launching a challenge
Such cases are becoming more and more commonplace so if you suspect a Will is invalid, what can you do about it?
Mervyn Lebor and four relatives failed to overturn the Will of Golda Bechal
In English law, the legal grounds for challenging the validity of a Will are strictly defined.
The first is that there has been a lack of proper formalities
A will must be made in writing and be signed by the testator - the person making the Will - in the presence of two witnesses who must also each attest and sign the Will in his presence.
Alternatively the Will can be signed in the presence of the testator and at his direction.
If any of these requirements are missing, the Will is invalid.
To make a valid Will the testator must also have the requisite mental capacity.
He must be capable of understanding that he is making a Will and disposing of his assets on death.
He must also be capable of understanding the extent of his estate and appreciating the claims on that estate to which he ought to give effect.
Testamentary capacity may be lacking because of mental illness; commonly Alzheimer's disease or other forms of dementia.
But the issue also arises where a testator is terminally ill and heavily dosed with painkillers.
Lack of knowledge and approval
A testator must know and approve the contents of the Will.
If a Will is properly executed the person challenging its validity must prove that the testator did not know and approve the content.
However, if circumstances surrounding the Will are particularly unusual or suspicious, then the person seeking to rely on the Will has the burden of proving validity.
Circumstances which might prompt further investigation include the main beneficiary preparing the Will for the testator, or a carer preparing a Will on behalf of an elderly or infirm patient.
A successful allegation of undue influence must demonstrate that the testator was coerced into making the Will.
No physical force is necessary to prove coercion, but evidence that someone simply reminded the testator of his family obligations is not strong enough evidence.
Since the testator cannot give evidence directly, this is a difficult allegation to sustain - there may suspicion, but little hard evidence!
Forgery is notoriously hard to prove and is rarely pleaded on its own; usually it is coupled with an allegation of lack of knowledge and approval.
An expert's assessment of the signature is invariably required.
What to do?
If you suspect a Will is invalid on any of these grounds you should consult a solicitor.
Zoran Kostic argued that his father's bequest to the Tories was "delusional"
They will investigate the circumstances surrounding the preparation of the Will and enter a "caveat" at the Probate Registry to prevent a grant of probate being taken out in the meantime.
It is important to act quickly at the outset to prevent the estate being administered in accordance with an invalid Will and the assets being dissipated.
However, probate actions can be complex and there is usually a good deal of preliminary investigative work to be done before a claim can be formally issued.
Some cases may be ready for a hearing before a Judge within 12 months, but where the estate is large and the facts are complex it may be two to three years before a claim is heard.
Although mediation is becoming increasingly common in litigious claims, actions to contest Wills tend not to be suitable for this form of resolution and therefore the legal arguments must be rehearsed before a Judge.
Each case will have a unique set of facts which must be examined in detail before the likelihood of success can be determined.
Expense and delay
The costs involved in pursuing probate actions can vary considerably from under £10,000 up to £250,000 and beyond for the larger and more complicated claims.
If a Will is pronounced invalid any prior valid Will made by the testator will be admitted to probate in its place.
Where no previous Wills exist, the intestacy rules will apply to the estate so it is prudent to establish whether you would benefit from any previous Will or intestacy before pursuing litigation.
It is sometimes hard to accept that a testator may have cut someone out of his Will based on a rational and considered decision especially in light of the numerous reports of successful claims.
Nevertheless, if you launch an unreasonable court action and lose, the chances are that you will have to pay a good percentage of the successful party's costs from your own pocket in addition to your own legal fees.
The last few years have seen a number of important decisions concerning disputed Wills and there is no doubt that this specialised form of litigation is a growth area.
That said, probate litigation should not be embarked upon lightly; it is invariably expensive, likely to delay the administration of the estate and may mean that the testator's last wishes are ignored.
The opinions expressed are those of the author and are not held by the BBC unless specifically stated. The material is for general information only and does not constitute investment, tax, legal or other form of advice. You should not rely on this information to make (or refrain from making) any decisions. Always obtain independent, professional advice for your own particular situation.