In what Theresa May will claim is the “greatest extension of rights and protections for employees by any Conservative government” she will also commit her party to introducing statutory child bereavement leave and the right to request time off work for training.

The moves form part of a series of manifesto pledges aimed at rebranding the Tories as the party for workers. They will also include a crackdown on abuses in the so-called gig economy with new rules likely to extend maternity and sickness pay to workers who are at present classed as self-employed.

All listed companies will be required to appoint a non-executive director to act as an employee representative at board level, while new powers will be created to block takeovers that could have an impact on the sustainability of pension funds.

The policies, drawn up by the prime minister’s aides, mark a decisive shift away from the party’s traditional business-first approach and are likely to create tensions with industry.

● A new “statutory right to leave” for people whose family members require full-time care. The proposal would give workers the right to take between 13 and 52 weeks off while retaining their employment rights. The leave would not be paid but employees would be guaranteed to return to their job at their existing salary once the period was over.

● A new law to prevent employers discriminating against workers suffering from mental ill health. The Tories will amend the Equalities Act to protect people suffering from depression, anxiety and bipolar disorders from being unfairly dismissed.

● The party will also propose to introduce a two-week paid child bereavement leave and to guarantee planned increases in the national minimum wage until 2022.

A package of measures will aim to prevent corporate abuses after the BHS pension scandal. The Pensions Regulator will be given new powers to inspect takeovers that could have an impact on the sustainability of a pension fund. It will also consult on options to give employers the same rights as big shareholders to receive information about takeovers, asset disposals and significant reorganisations.

Last night senior business figures warned the Conservatives against introducing “new regulations and burdens” at a time when Brexit was already causing “significant uncertainty”.

This will be rejected by Mrs May, who will say that leaving the European Union presents an opportunity to redefine the relationship between employers and employees.

“I said I would use Brexit to extend the protections and rights that workers enjoy, and our manifesto will deliver exactly that,” she is expected to say on a campaign visit today. “By working with business, reducing taxes and dealing with the deficit we have delivered steady improvements to the economic prospects of working people. Now is the time to lock in that economic growth and ensure the proceeds are spread to everyone in our country.

“Our plans will be the greatest expansion in workers’ rights by any Conservative government in history.”

Mrs May will promise to implement the recommendations of the Taylor review into the gig economy. This is expected to conclude that a growing number of companies are abusing the law by taking on supposedly self-employed workers for jobs previously carried out by salaried staff. It is expected to call for much stricter rules on what constitutes genuine self-employment, with companies banned from imposing any “control” or sanction over workers who are classed as self- employed. It may also recommend extending statutory maternity and sick pay to genuine self-employed workers.

There will be a renewed focus on helping people to return to the labour market after taking time out either to look after children or to care for family members.

Damian Green, the work and pensions secretary, said the new right to leave was aimed at people who needed to “sort something out over a couple of months” before returning to work with certainty. The carer’s allowance of £62.70 a week is not designed to be lived on, he added.

The Tories will pledge to introduce a programme of “returnships” in the private and public sector, with the promise of new funding to pay for it. Employees who want to retrain or to improve their skills will have formal rights to request time off from their employer.

Speaking to the Today programme on BBC Radio 4, Mr Green said that the government had “completely revived the idea” of apprenticeships and would now allow workers of all ages to “reskill” in order to keep pace with technology.

Adam Marshall, director-general of the British Chambers of Commerce, said that industry would view the manifesto pledges with caution. “While there is little appetite in the business communities I represent for a roll-back of employment rights as the UK leaves the EU, businesses worry about the prospect of costly or bureaucratic new obligations, no matter how well intentioned,” he said.

Sir Michael Fallon, the defence secretary, admitted yesterday that a key pledge on housing would not have new funding. Mrs May had told The Sunday Times that the Tories would support local authorities to build a new generation of council homes to help to fix the “broken” housing market. Ministers refused to specify how many new homes would be built.

Analysis: Red Tories learn from Brussels
It is already being described as the Tories’ “red” manifesto. New workers’ rights, a crackdown on corporate excess and a symbolic pledge to launch a new programme of council house building.

Even before the full details are released later this week one thing is clear: Theresa May intends to use her own electoral mandate to move the party in a very different direction from that of her predecessor.

Part of this new approach is cold electoral calculation. Mrs May and her aides see Jeremy Corbyn’s leadership of Labour as a unique opportunity to re-draw the electoral landscape.

Working-class voters in northern Labour heartlands are, for the first time, considering something that has been previously unconscionable: voting for the hated Tories. This week’s manifesto will be an attempt to show them that Mrs May has their interests at heart. The lesson she drew from the Brexit referendum was that the vote to leave the EU was as much a howl of outrage at Westminster as it was a rejection of Brussels. Many feel that successive governments have been too close to business. One of the ironies of Brexit is that Mrs May seems intent on taking a more European and interventionist approach to capitalism just as we’re heading for the exit door.