CATHY Woodhead this week said she could sue her former husband for defamation - but only if the costs were paid by someone else.

It could prove an expensive business. Libel specialist lawyers forecast that she would have to raise a fund of pound;500,000 to bring an action against her ex-husband.

The main factor driving up costs would be the gathering of evidence about events more than 20 years ago. The trial itself would probably run for at least seven days. Both sides would have at least one QC and a junior barrister supported by a team of solicitors.

If Mrs Woodhead lost, she would have to pay the defence costs as well as her own, bringing the total easily above six-figures and possibly up to half a million.

Recently, the Government has brought libel actions under the ambit of conditional fees - the so-called “no win, no fee” system. The option would be available to Mrs Woodhead if she could convince a law firm that the case had a solid chance of success. However, she would be advised to take out as much as pound;50,000 insurance to cover the defence side’s costs in case she lost the action.

If the action were brought after April 26, when the new civil justice reforms kick in, an attempt could be made to keep costs down by “fast-tracking” the case. That would limit the damages claim to less than pound;15,000 and force the trial to be heard in one day. But it is inevitable that the defence would object to such a move, arguing that calling such old and complicated evidence would require a longer hearing.