Two people suspected of illegally leaking CCTV footage of Matt Hancock and his aide kissing will not be prosecuted due to insufficient evidence, the information watchdog said.
The footage leaked to The Sun last year, showing Mr Hancock kissing Gina Coladangelo in his departmental office, led to him resigning as health secretary for breaking social distancing rules.
It also prompted a criminal investigation by the Information Commissioner's Office (ICO), with two homes raided and computers seized last July.
The ICO said: "Forensic analysis revealed that the leaked images were most likely obtained by someone recording the CCTV footage screens with a mobile phone.
"Six phones retrieved during the execution of search warrants did not contain the relevant CCTV footage."
The ICO said it had found "insufficient evidence to prosecute two people suspected of unlawfully obtaining and disclosing CCTV footage from the Department for Health and Social Care".
It has now closed its criminal investigation, which it launched after receiving a report of a personal data breach from the health department's CCTV operator, EMCOR.
The ICO said it had had a legal duty to launch the investigation "given the seriousness of the report and the wider implications it potentially had for the security of information across government".
It looked at whether there had been a breach of the 2018 Data Protection Act.
Mr Hancock left his wife of 15 years - with whom he has three children - for Ms Coladangelo after the revelations.
The health department said: "We note the outcome of the ICO's investigation and will continue to work with them to learn any lessons from this incident.
"We take the security of our personnel, systems and estates extremely seriously.
"Since this incident, we have worked with security specialists from across government to review procedures and will keep them continually under review."