A widely awaited divorce hearing kicking off in the Supreme Court today is likely to prompt renewed pressure on the government to reform 'outdated' family law.

The UK's highest court will begin hearing Owens v Owens after the Court of Appeal ruled that it could not interfere with a lower court's decision to refuse to grant Tini Owens a decree nisi, even though the judge had correctly found that the marriage had broken down.

Lady Hale, Supreme Court president, has described the case as a 'rare example of the court rejecting a behaviour petition on the ground that the husband's behaviour was not objectively bad enough to make it unreasonable for the wife to live with him'.

Tini Owens is being represented by solicitor Simon Beccle, a partner at London firm Payne Hicks Beach. Beccle said the appeal is not about the Supreme Court changing the law nor is it about the concept of 'no-fault divorce'.

'Rather, it concerns the proper interpretation and application of section 1(2)(b) of the Matrimonial Causes Act 1973, the statute that applies when one person wishes to divorce another in England and Wales. That legislation provides that a divorce may be granted on the sole ground that the marriage has broken down irretrievably. Mrs Owens needs to satisfy the court that Mr Owens has behaved in such a way that she cannot reasonably be expected to live with him,' Beccle said.

At present, couples are unable to divorce without blame unless they have been separated for two years. A spouse has to wait five years if their former partner does not agree to a divorce. Family law group Resolution has called current legislation 'outdated' and 'unfair'.

Hale permitted Resolution to intervene in the case 'because they concentrated on the legal rather than the policy arguments. What the current law is and what the law ought to be are quite separate matters'.

Beccle says a successful outcome for his client 'is likely to mean that there is less need for one party to cite detailed and often unpleasant particulars of how the other has behaved, with the focus being instead on the effect the behaviour has had on the party seeking a divorce, regardless of whether it is objectively bad or otherwise blameworthy'.