The much-criticised watchdog that scrutinises the jobs UK ministers can take after leaving office will be formally scrapped on Monday as part of a wider shake-up of the ethics structure in government.

The Advisory Committee on Business Appointments (Acoba), described by critics as fundamentally toothless, has been closed, a Cabinet Office announcement said, with its functions taken over by two existing regulators.

At the same time, a new organisation called the Ethics and Integrity Commission will oversee the work of a series of other regulators, the centrepiece of what Keir Starmer has promised will be a robust new approach to government and to any ministerial misdeeds.

Also from Monday, a previously announced ban on severance payments for ministers who lose their job after a serious breach of the ministerial code comes into force.

In the change, first revealed by the Guardian in July, former ministers who take up new jobs in a serious breach of the rules for post-government appointments could be asked to hand back any severance payment.

The standard severance payment for a departing minister is a quarter of their ministerial salary, as long as they are not given a new frontbench post within three weeks. For cabinet ministers this equates to just under £17,000.

Under the new system, those who serve for fewer than six months will be expected to not take the payment, while those who get a new ministerial job within three months will be asked to not take a salary until the end of that three-month period.

With Acoba abolished, Sir Laurie Magnus, Starmer’s independent adviser on ministerial standards, will adjudicate on job appointment rules for ex-ministers. The Civil Service Commission, which regulates recruitment into the civil service, will do this for former civil servants and government special advisers.

The Ethics and Integrity Commission is, however, not an entirely new organisation, but takes on the work of the existing Committee on Standards in Public Life (CSPL), which was tasked with giving the prime minister advice on broader ethical standards.

The commission will be headed by the CSPL’s existing chair, Doug Chalmers, a former soldier who ended his military career as deputy chief of defence staff.

In a letter to Chalmers marking the new commission, Starmer said one of the organisation’s tasks should be to make sure ministers and civil servants help other public servants meet their responsibilities under the still-to-be-passed Hillsborough law, which obliges them to act with honesty and candour and avoid cover-ups.

The announcement said: “The prime minister has made clear public service is a privilege and is committed to showing how politics can be a force for good. The government’s manifesto pledge to set the highest standards in public life to restore trust between the public and politics.”

Nick Thomas-Symonds, the minister of state for the Cabinet Office, said the Ethics and Integrity Commission “will play a central role” in ensuring the government delivers its pre-election promise to uphold the highest standards in public office.

It remains to be seen how big an impact will come from a minor reorganisation of the framework for monitoring ethical standards, and the creation of a new, top-level watchdog, the job of which is not to enforce rules but to help make sure others to do so.

As well as Magnus’s office and the Civil Service Commission, other ethics-related bodies for public life include the parliamentary standard commissioner, parliament’s Independent Complaints and Grievance Service, the House of Lords Appointments Commission, the Electoral Commission, the UK Parliamentary Standards Authority and the Registrar of Consultant Lobbyists.