Workers will be automatically entitled to flexible hours from the first day in their job under a major overhaul of employment rights unveiled in the King’s Speech.

Existing rights to request family-friendly hours, which put the onus on the employee to ask for them, will be changed to a presumption for all workers to have the benefit.

There will be exemptions for jobs and sectors that are time-critical or where different shift patterns are not suitable.

Flexible working can include starting later to allow for taking children to school or other childcare reasons, as well as working longer shifts over fewer days of the week.

The new laws will not automatically give the right to work from home.

The overall package of workers’ rights reforms will be overseen by Deputy Prime Minister Angela Rayner, who will chair a Cabinet committee designed to drive forward the legislation, which met for the first time on Wednesday following the King’s Speech.

It will bring together ministers from the Department for Work and Pensions, the Treasury, the Department for Business and Trade, and the Cabinet Office.

The Employment Rights Bill will be led by Business Secretary Jonathan Reynolds and will be introduced within the first 100 days of the new parliament.

The reforms were described by the government as the “biggest upgrade to workers’ rights for a generation”.

Some measures will not require primary legislation, such as introducing a genuine living wage for workers, including those in the poorly paid social care sector.

This is also the case for the “right to switch off” – where employees will not be required to respond to emails or calls from their bosses after working hours.

The package of reforms, which apply to Great Britain, also includes:

• A ban on exploitative zero-hour contracts;
• Allowing workers to receive reasonable notice of any changes in their shifts, and compensation for any hours cancelled or cut short;
• An end to “fire and rehire” practices;
• Rights to parental leave, sick pay and protection from unfair dismissal available from day one on the job, while not axing probationary periods;
• Removal of the lower earnings limit for statutory sick pay, to make it available to all workers;
• Outlawing the dismissal of women who are within six months of returning to work after having a baby.

Gary Smith, general secretary of the GMB union, said: “After 14 years of Tory chaos, Labour’s first King’s Speech is the breath of fresh air the country has been looking for.

“The Employment Rights Bill contains much that will make a big difference to the lives of working people. GMB members will welcome proper national terms and conditions for school support staff, a fair pay agreement for social care workers, and the tackling of vindictive and outdated practices used by bad bosses.

“It’s good to see a much-needed focus on industrial strategy and skills, areas of critical importance to growth and prosperity that have been neglected for too long.

“The people of our country voted for change and this King’s Speech is a serious and comprehensive response.”

However, Tina McKenzie, policy chair of the Federation of Small Businesses, said: “Small businesses are increasingly worried about the developing employment rights package.

“More than nine out of ten small employers say they are concerned about the prospect of increased costs and risks when they employ people, and there were no commitments within this to look after small employers who will struggle the most.”