Rules governing jobs civil servants can take on after leaving government are not being applied consistently, the public spending watchdog has found.
Officials must get departments’ say-so before taking up private sector roles.
But the National Audit Office found firms were not being notified of conditions attached to jobs, such as lobbying bans, designed to stop abuse of influence for commercial gain.
It also said jobs were being approved retrospectively, against the rules.
The business appointment rules, which are overseen by the Cabinet Office, are designed to ensure that officials uphold civil service values for a period of two years after leaving Whitehall and do not take on work that would give “cause for justified public concern, criticism or misinterpretation”.
Specifically, they are designed to mitigate against the risks of a civil servant being influenced in their duties by the prospect of future employment or employers gaining an unfair advantage by hiring someone who had access to commercially sensitive information or knowledge of future government policy.
Senior officials are expected to get clearance for new jobs if they have been involved in policy areas or regulatory decisions affecting their prospective employer, have had dealings with them or have had access to privileged information within the past two years.
But the NAO said it was not apparent that any applications had been blocked while it could not be certain all relevant appointments had been submitted for approval.
In 2015-16, 271 senior civil servants at levels one or two – including directors and deputy directors and some special advisers – left, but only 67 decisions relating to new jobs had been published, it said.
Since February 2016, it said details of 170 decisions had been published, the vast majority relating to officials seeking to switch careers to work in the private sector, either for companies or charities.
Of the 170, 32 had no conditions attached to them, 47 had one condition, 64 had two conditions and 27 had three conditions.
In 95% of cases, the conditions included a ban on lobbying government while 50% of them contained a confidentiality clause.
However, the NAO said only one department had consistently informed employers of the conditions, as required by the rules, while only five notifications had been sent in the past five years.
The watchdog said it had been told by one department that their former officials were expected to share the information with their new employers.
Among other breaches, four departments had approved retrospective applications, which the rules state should not normally be accepted, while no department could provide reassurances that former employees remained compliant with the rules for two years after leaving as required.
The NAO warned of a lack of central oversight of the rules in government to ensure compliance but does not make any recommendations as to how the system can be tightened up.
The report does not cover permanent secretaries, departmental heads who must separately seek the approval of the Advisory Committee on Business Appointments before taking up new positions.
Labour said the report showed how “money and power stays within a closed circle”.
“There is complete lack of oversight and the system is toothless,” said shadow minister John Trickett.
The Lib Dems said there was a “revolving door” between government and big business.
“It shows that the government have a system that doesn’t work, has no teeth and isn’t even being properly implemented,” said outgoing leader Tim Farron.