When signing your last Will, with the required formality of two witnesses, you might reasonably expect that to be the last word on what happens to your estate (unless you yourself decide to change in future). Testamentary freedom ie the right to leave your money as you wish is a longstanding and fundamental principle of English law as well as that of most US states. People often want to set out how their family will benefit, or to know that their wealth will be used to benefit their preferred causes after they die. Depending on one's viewpoint it is unfortunate that that sense of control is not always well founded or it is a welcome development over the past decades that the sometimes harsh and capricious ways that freedom is exercised can sometimes be tempered.

There are several ways in which people in England and Wales do not have as much control as they might believe.

One sad, and often unforeseen, situation arises where a person loses capacity to make decisions for themselves, perhaps as the result of an accident or a serious illness. In this situation the Court of Protection can make a 'statutory Will' on their behalf based on what it considers is in their "best interests" - however as my colleague Stephen Richards has argued, this may not chime with what the person's wishes and feelings would truly have been.

The Court of Protection can (and sometimes does) rewrite a person's Will whilst they are still alive - or make a Will when they had never bothered in their lifetime. Its cases are usually anonymised to respect the confidentiality of the incapacitated person whose Will is being rewritten. But a public (because the person in question Gladys Meek had died) example, of the Court's power being used came in Jones v Parkin. Gladys' niece and great-niece had helped themselves to 'extravagant gifts' from Glady's' funds including cars, jewellery, and designer handbags. The Court removed them from control of Gladys' money and then approved a statutory Will whereby Gladys' estate went to two friends and charity (whereas otherwise, as she had never made a Will, the niece and great-niece would have inherited in any event on intestacy). Gladys might well have wanted to exclude them from benefitting if she had capacity but she did not and so the Court made a decision on her behalf.

There are also several ways in a person's wishes may be undermined after their death.

Financial provision claims, for example, are relatively common. This is where a dependent or certain close relatives are able to claim that (more) provision should be made for them.

Things can become particularly contentious where the testator did not wish to leave anything to an estranged child. The Court has a wide discretion to decide that it was not reasonable for the deceased to leave nothing and so can override the deceased's wishes. Famously, Mrs Mitson took her mother's chosen charities all the way to the Supreme Court in pursuit of financial provision despite the fact she and her late mother had not spoken for many years prior to her mother's passing.

Financial provision claims can stop evident injustices. Had Mrs Bhusate not been allowed to claim 26 years out of time (in Bhusate v Patel) in her late husband's estate she would have been left with literally nothing at the expense of his children from a first marriage.

Of course, making some provision for those who might reasonably hope to benefit may reduce the risk of claims. Particularly if that is coupled with what is called a forfeiture clause, ie one which stipulates that the legacy fails if the beneficiary tries to claim more (because he or she has to assess the bird in the hand against the risk of ending up with nothing).

Proprietary estoppel claims are less common but seem to occur with surprising frequency in farming families. This kind of case arises where a person argues that the deceased has broken a promise to them on which they relied to their detriment- an example might be where a son or daughter helps to run a farm on the understanding that they will inherit it, only to find that it has been left equally to them and siblings who made their own career elsewhere. If the person can show that there was a promise, that they took significant action because they were relying on that promise, and that this action was burdensome or detrimental, a court can order the Will's provisions are overridden. Of course the main witness - the person alleged to have made the promise - is usually unavailable to give evidence by virtue of being dead...

Of course, the main way to obstruct your Will is a full on challenge to its validity - time after time Wills are challenged by someone aggrieved they did not get more alleging lack of capacity, or undue influence, or even fraud. The idea that someone can attack your Will sets alarm bells ringing - how dare they, 'it shouldn't be allowed'. But what if the Will was made when mental incapacity had set in or where the main beneficiary just happens to have been involved in the Will making process. The ability to challenge Wills means that professionals who take instructions and draft Wills take much greater care and operate to a higher standard than might otherwise be the case.

One factor which lends itself to compromise is expense. Probate trials are inordinately expensive. And there is always some element of risk because - as previously noted - the main witness by definition is no longer with us. So it will often make more sense for protagonists to settle a claim than to fight it in court. There is a common misconception that costs come out of the estate, leading to the common reference to Jarndyce v Jarndyce. In fact it is much more common for the loser to pay the winner's costs (as well as their own) - so losing can be absolutely catastrophic. But winning can sometimes be pyrrhic victory as costs are not always recoverable. So, despite the deceased's firm instructions that all should go to the favoured child the estranged child receive nothing, favoured child is often well advised to offer their sibling something.

Some protagonists can afford to pay what it takes to uphold a Will - but those without deep pockets need to think very carefully about letting principles override commercial analysis.

The above may sound like a litany of (some of the) limitations to the ancient principle of testamentary freedom. But in reality they might be better viewed as a series of imperfect checks and balances which seek to preserve that freedom whilst mitigating its excesses and preventing abuse. And most well drafted Wills should be difficult to challenge. If testators take the care to brief their adviser properly, think about the promises they've made, and the obligations they owe, and the adviser notes carefully their client's reasoning - having taken care to ensure that no-one with a financial interest is involved in the Will making process - a Will should withstand most challenges once its maker has passed on. There is a reason for the traditional barrister's toast to the homemade Will!

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.