Some interesting commentary here from The Times about the case of Dawn Webb, who inadvertently revoked her Will by getting married, meaning her estate would pass under the intestacy rules rather than in accordance with her Will. 

This meant that her three children are left with very little, whilst her new husband will receive the vast majority of her estate. The children are bringing a claim saying that the Will should be changed so as to make better financial provision for them. 

The Times goes on to comment about how to make your Will watertight - the best advice on this is that you can't. There is no such thing as a "watertight" Will, if what that is meant to mean is that the Will can't be challenged. 

What there can be is a well-constructed Will that is prepared with an eye on minimising the value of any future challenge to that Will - but it is simply not possible to create a Will which cannot be challenged. No solicitor or will-drafter should be offering such a guarantee to their client(s). 

The proper question is how to make the value of any challenge as small as possible. One of the great double-edged swords of our legal system is that everyone has the right to have their day in Court, even if that day is on a Will challenge with limited or no merits. Access to justice is sometimes an uncomfortably close neighbour to frivolous or abusive claims. Similarly, the current position on the interaction of Wills and marriages is also in urgent need of review.