Sir Keir Starmer has insisted bosses are not “knocking on my door saying they want to rip up employee rights” as he defended his plan to tackle bad working practices.

The Prime Minister, who vowed to “rewrite the rules of our economy” and forge a new partnership between government, business and workers, rejected criticism of his plans – which the Tories have dubbed “French-style union laws”.

The Institute of Directors (IoD) has warned that business leaders will be less likely to hire new workers as a result of the Government’s planned employment rights legislation.

But Sir Keir, in the first TUC Congress address by a prime minister since 2009, told unions there was a “mood of change” in the business world.

His speech was given a standing ovation from parts of the audience although a heckle of “tax the rich” could also be heard in the Brighton conference hall.

Sir Keir told trade unionists: “Business leaders are not knocking on my door saying they want to rip up employee rights.

“They don’t tell me the problems they face will be solved by coming for trade unions.

“They want fair taxes, high skills and the long-term stability to invest.

“And that chimes precisely with what trade unions up and down the country tell me they also want.

“Working people want good companies to make profits, attract investment and create good jobs.”

Measures in the Government’s plans include banning “exploitative” zero-hours contracts, ending policies of fire and re-hire, and making parental leave, sick pay and protection from unfair dismissal available from day one in a job for all workers.

Flexible working will be the default from the first day in a job while it will be unlawful to sack a woman who has had a baby for six months after she returns to work.

The Employment Rights Bill will also remove restrictions on trade unions, including the Conservative government’s controversial law aimed at ensuring a minimum level of service during strikes.

Sir Keir described the Conservative measures as “cheap and vindictive attacks on this movement”.

An IoD survey of 715 business chiefs found 57% said they would be less likely to recruit staff as a result of the Government’s plans.

Alexandra Hall-Chen, principal policy adviser for employment at the IoD, said: “Business leaders are concerned about the impacts of the proposed new reforms on the cost of employing staff.”

Shadow business secretary Kevin Hollinrake said there were “howls of opposition from business leaders about his (Starmer’s) plans to strengthen the unions and force unworkable proposals on employers that will cost jobs”.

Sir Keir balanced his promise of a new package of workers’ rights and a new era of more positive industrial relations with a warning of future pay restraint for public sector workers.

His appearance came as he was under fire from Labour MPs, unions and campaigners over the decision to means-test the winter fuel payment, with a Commons vote just hours after his TUC speech.

Sir Keir said there were more “tough decisions” to come and “pay will inevitably be shaped by that”.

He has faced union demands to commit to full pay restoration, with a series of bumper wage rises to make up for years of below-inflation deals.

But Sir Keir told the TUC: “This Government will not risk its mandate for economic stability, under any circumstances.”