High Court disputes over wills and inheritance have risen three-fold due to the break-up of the nuclear family, longer life spans and larger estates.

Last year 228 such disagreements were resolved by judges, compared to only 83 in 2006. However, the actual number of legal disputes over wills is likely to be far higher because the vast majority are resolved before they reach the High Court.

Many modern day disputes are caused by an increasing tendency for couples to live together for a long time without getting married. Sometimes wills are contested by the family of the deceased, on other occasions by the person he or she is living with. Even people who aren't living with their partners have been known to join the fray, particularly if they can claim to have been maintained by the deceased before death.

The claims of illegitimate or step-children can also be a cause of rancour. If a man helps raise any child with regular maintenance payments there could be grounds for legal action if he or she is left out of the will. In modern times more people are challenging wills on the grounds of the alleged mental incapacity of the person making it.

Another factor is the increasing tendency for people to leave sometimes vast amounts of money to charitable institutions.

"Money brings out the worst of people in death," said Sarah Phillips, of the law firm Thomas Eggar. "The break-up of the nuclear family is a major factor. There are lots of cases where someone has two marriages and two lots of children. When they die they leave everything to the second wife, assuming she will do the right thing by the children of the first marriage. Often it's the person who would normally have resolved the issue, perhaps by knocking people's heads together, is the one who's no longer there."

Fay Copeland, of Wedlake Bell, the City law firm, said: "We are seeing more and more cases where disputes arise from spouses from first, second or even third marriages. Things get even more complicated when it comes to provisions for the children of each marriage. People can end up very displeased with the size of the slice of the estate they receive and have fewer qualms about taking take matters to court if they feel they have been treated unfairly under the will."

Ms Copeland said: "Many older people feel disconnected to their children nowadays, as families are increasingly dispersed across the UK and worldwide, and in many cases have no communication at all. We have seen an increase in the number of people who decide to leave their sizeable estates to charitable institutions, as they feel closer to these than to their own children. These can range from the legendary local cat shelter to medical research charities. Disgruntled children then challenge their parents' wills, often on the grounds of mental incapacity."

Lawyers insist that do-it-yourself wills are often a false economy. Mrs Phillips said: "Unless your affairs are the most straightforward in the world, the pack you buy from W H Smith may not be good enough."

Published in The Telegraph, 27 January 2009