The number of people challenging the inheritance left by their relatives or partners has risen by 38% over the past year, according to figures obtained by City firm Wedlake Bell.

Data from the High Court shows that the number of cases launched by people, including children, spouses and cohabitees, who feel they have not been properly provided for in wills or on intestacy went up from 80 in 2008 to 110 in 2009.

It reveals a ten-fold increase in such cases over the last three years, increasing from just 10 in 2006.

Wedlake Bell suggests the rise in disputes is being driven by the recession, as the value of many estates slumps, combined with the growing complexity of family structures and out-dated inheritance and intestacy laws.

It says the increasing popularity of DIY will kits has also added to the risk of disputes.

Fay Copeland, a partner in Wedlake Bell’s private client team, said: ‘The recession has had a hugely detrimental impact on the size of estates with the value of family homes, shares and other assets having all dwindled. As the pie gets smaller, the temptation for beneficiaries to fight for a bigger slice increases.’

She said the scope for inheritance disputes increases dramatically with the number of marriages, divorces and children that are involved.

‘Anyone who was in some way financially dependent on the deceased at the time of death may be able to make a valid claim, so that also applies to children outside marriages, cohabitees and even mistresses,’ said Copeland.

Copeland said the likelihood of disputes becomes even higher where someone dies without making a will, because the estate is then divided according to intestacy rules, many of which where drawn up to reflect the social landscape and family structures of the 1950s and even the 1920s.

She said: ‘[The laws] make no allowance for the financial needs of dependants or the extent to which they were financially dependent on the deceased.'

The Law Commission published a consultation paper that reviewed the rules on intestacy and family provision claims on death last year. It closed in February 2010 with a report and draft bill due to be published in 2011.

A report by the National Centre for Social Research recently suggested that a change in family relationships pointed to a need to amend the current intestacy rules.