The UK's second biggest union is threatening "naming-and-shaming" for employers who fail to hold pay audits in an effort to expose unequality between men and women.

Officials point to statistics that suggest women earn up to 18% less than men.

Amicus - which was formed from a merger between the MSF union and the AEEU - is holding its first women's conference in London on Saturday.

The pay gap will be at the top of the agenda as the new union starts to flex its muscles.

Amicus wrote to more than 6,000 employers in manufacturing and finance at the end of last year asking them to carry out pay audits.

Companies' silent

The aim was to reveal any discrimination in pay policy between men and women.

Most of the companies have failed to respond.

Now if firms refuse to carry out a review the union is threatening to name and shame them on 6 March.

Union leaders want the government to introduce legislation to force companies to carry out pay reviews.

The Confederation of British Industry recognises that something needs to be done about the pay gap but does not think bosses are to blame and strongly opposes compulsory pay reviews.