By Ian Dunt

Legislation which would force public bodies to prevent class discrimination has been published for the first time in British history.

The single equality bill was presented to the public today, before being debated and voted on in the Commons.

"The recession has put a focus not just on people's fears for today but on their hopes for tomorrow," women's minister Harriet Harman said.

"That hope is for a fair and equal society which is stable and prosperous."

It brings together all the UK's equality legislation, with several new pieces of law which have divided commentators and set down the groundwork for battles to come.

Public bodies will have an obligation to reduce inequality, for instance by encouraging parents from poor backgrounds to apply to successful local schools.

Private companies will also feel the effects of the bill, with firms being forced to provide audits of their pay to staff, so gender gaps can be spotted.

Companies which consistently pay their male colleagues more will be named and shamed. Firms with more than 250 employees will have until 2013 to reveal the salaries.

The scheme also applies to public-sector bodies with 150 employees or more, including Whitehall departments, local councils, strategic health authorities, regional development agencies and the Met - as well as ministers.

Shadow women's minister Theresa May said the plan would make no difference to the gender pay gap.

"We're concerned that too many of the proposals in this bill will be bureaucratic and expensive without providing real results," she said.

"For example, Labour's proposal for compulsory pay audits for all companies, rather than those proven to have broken the law, will simply waste time and money without making any difference to pay discrimination."

The business sector is already smarting from the proposal.

David Frost, director general of the British Chambers of Commerce, said: "Last Wednesday the chancellor positioned business at the heart of the economic recovery in the Budget and said all actions were to help reinforce that position.

"Yet within days the government is announcing that businesses are to be burdened with a requirement to carry out gender pay audits in the equalities bill. Clearly some sections of government just don't get it, that business is critical to recovery."

Trade unions responded fiercely, with Brenden Barber, TUC general secretary saying audits were the most effective way to get movement on equal pay.

"The UK will never tackle the problem of unequal pay until there are systems in place exposing the huge gap between what men and women doing similar jobs in the same workplaces are paid," he said.

"The business lobby will of course complain loudly about what they see as another burden on business, but pay audits are the very least employers should do if we are to finally get rid of low and unequal pay for female workers in the UK."

There is also an outright ban on age discrimination and a general requirement for public bodies to actively think about the needs of minorities, rather than just react to problems.

This will bring gay rights into the same category as race or disability.

Seemingly innocuous, it will almost certainly provoke political earthquakes later on, with teachers in faith schools likely to rebel over discussing homosexuality in the classroom.

The Equality and Human Rights Commission (EHRC) is ploughing a lonely path through the proposals.

On the one hand, its finding are part of what has prompted action in the first place, with a recent report showing City bonuses for women are 79 per cent lower than for men.

But the Commission is uncomfortable with the audit suggestion, raising concerns that forcing firms to conduct equal pay reviews could provoke a flurry of litigation claims.

Instead, the ECHR wants an amnesty period for employers to tackle the problem internally without resort to the tribunal process.