P&O Ferries faces criminal probe over sackings
P&O Ferries faces a probe into the controversial no-notice sackings of nearly 800 members of staff.
The Insolvency Service has launched criminal and civil investigations into the circumstances around the redundancies.
In a letter, it said it would consider "prompt and appropriate action" if the law was broken.
Grant Shapps has also asked the service to consider disqualifying its boss from acting as a company director.
The transport secretary made the announcement as part of new pay plans for the ferry industry this week after P&O Ferries sacked 786 employees without notice and replaced with them with agency workers.
P&O Ferries said on Friday that all but one of the sacked employees had taken steps to accept the redundancy offer made by the company. One former P&O worker, John Lansdown, told the BBC he did not respond to the company's offer.
The company declined to comment on the Insolvency Service's investigation when approached by BBC News.
Business Secretary Kwasi Kwarteng tweeted that he and Mr Shapps would follow the new investigations into P&O Ferries closely as they develop.
The Insolvency Service has the power to investigate allegations of corporate abuse.
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Mr Shapps said earlier this week that his new package of measures would force P&O Ferries to "fundamentally rethink" its decision.
He urged ports to block ferries from docking if they do not pay their crew the UK minimum wage, with plans to create new laws.
Ferry industry groups, however, hit out at the transport secretary's plans, with the UK Major Ports Group saying they should not have to "be the police for the labour practices of ferry companies".
Unions also expressed disappointment that the plans did not go far enough for workers who had already lost their jobs.
P&O Ferries' boss Peter Hebblethwaite admitted that the firm knowingly broke the law by not consulting with unions and planning to compensate workers instead.
The firm said previously that staff would be offered £36.5m in total - with about 40 getting more than £100,000 each.
P&O Ferries said some employees were set to get 91 weeks' pay and the chance of new employment, and no employee would receive less than £15,000.
Mr Hebblethwaite has insisted that a U-turn on the redundancies would cause the company's total collapse, leading to a loss of an additional 2,200 jobs.
He told MSPs this week that P&O had "painstakingly explored all possible alternatives", but that it could not expect "unconditional support" from parent company DP World for the business without a plan to become viable after making a £100m loss year-on-year.
Mr Shapps branded the executive a "pirate of the sea", accusing him of "disgracefully shredding the reputation" of the company.
However, Mr Hebblethwaite said he would not step down.
He said he felt compelled "to discharge my duties for this historical company" and provide "the effective operation of the trade routes upon which this country depends".
"I will therefore continue to do my utmost to ensure that this company has a sustainable business for the future."