The Insolvency Service, which launched a criminal investigation into the dismissals in March, said prosecutors had concluded there was no realistic prospect of a conviction. The cruise line sparked nationwide protests when it fired hundreds of staff without warning via a recorded video message. P&O, which claimed it had to act fast because it was losing £1m a day, brought in cheaper agency workers to replace the employees. Legal experts said they believed P&O had acted illegally by not advising on the redundancies and the company’s boss admitted breaking employment laws. Anger worsened this week when the company’s owner, DP World, reported profits of £736m in the six months to the end of June. And transport secretary Grant Shapps tried to force the company to reinstate workers with a package of measures, including asking ports to refuse to deal with P&O. He also called on company boss Peter Hebblethwaite to resign. During parliamentary hearings, he admitted that his company had broken the law requiring them to notify staff. Business secretary Kwasi Kwarteng asked the Insolvency Service to investigate whether wrongdoing had been committed. A spokesman for the Insolvency Service said on Friday night: “Following a full and thorough criminal investigation into the circumstances surrounding the employees who were made redundant by P&O Ferries, we have concluded that we will not be bringing criminal proceedings.” An independent senior prosecution lawyer reviewed the investigation and decided there was no realistic prospect of a conviction, the spokesman added. However, the civil investigation by the Insolvency Service continues.