A top West Midlands' lawyer has commemorated the 30th anniversary of the Sex Discrimination Act by warning that up to half of women currently at work will suffer harassment.

Fergal Dowling, partner and head of employment with the Birmingham office of Irwin Mitchell, says many employers in the region are risking adverse tribunal rulings and potentially unlimited payouts, over harassment and discrimination against women in areas such as preg-nancy rights and pay, and by not having formal, written policies in place.

"Although the harassment of women at work may not be quite as overt and visible as it was when the Act took effect three decades ago, it certainly hasn't gone away," he said.

"Recent cases suggest the problem has become increasingly sophisticated and subtle. While women still endure the kind of verbal sexual abuse which has been going on for decades, they also now often face harassment by text and e-mail.

"According to the Equal Opportunities Commission, the number of sexual harassment complaints has risen since 1975, with 50 per cent of women in the workplace now complaining about the problem. This suggests a staggering number of women in the labour force will be mistreated in this way during their careers."

Mr Dowling's warning follows the recent case in which former £350,000-a-year banker Stephanie Villalba took her case against Merrill Lynch for wrongful dismissal to appeal, after she made a sex discrimination complaint against her boss and was sacked in 2003.

Among Ms Villalba's allegations are that she was told to sit 'in the stewardess seat' and serve drinks to male colleagues during a flight on a corporate jet.

Hers is one of several high-profile cases against financial institutions involving complaints of sexism.

Halifax-based HBOS is currently facing an £11 million claim from asset manager Clare Bright, who was in charge of a portfolio worth £140 million, alleging her manager had "disrespected, demeaned, overruled, micro-managed and humiliated" her, because of her gender.

In another case, Dresdner is facing a class action from six female employees claiming they were marginalised and denied promotion while male colleagues visited strip clubs and took part in humiliating sexual banter.

Mr Dowling said: "These allegations and statistics highlight the need for employers in the West Midlands to continue to address the treatment of the 70 per cent of women who now work. Importantly, however, a third of working women are now in management positions, compared to less than two per cent when the Sex Discrimination Act was passed 30 years ago, and 14 per cent are company directors, an increase of nine per cent during the period.

"One potential lesson for employers from the current cases is that mistreatment isn't just suffered by junior members of staff, who may be less able or willing to retaliate against it, but is also endured by the growing number of women in senior positions, who may - quite rightly - be much less tolerant.

"Sexual harassment is the fourth most common source of complaint by working women after pregnancy and maternity matters, pay and the work-life balance. Thirty thousand UK women a year are sacked, made redundant or leave their jobs because of alleged pregnancy discrimination, while part-time women workers typically earn 40 per cent less - and full-time staff almost 20 per cent less - than their male counterparts.

"Pay discrimination is a particularly important area for employers, given the possibility of tighter laws after the Department for Trade & Industry's current talks with Britain's unions. Firms could face investigation by the new Commission for Equality and Human Rights."