The battle for control of regional publisher Johnston Press has begun in earnest after the company’s biggest investor submitted a formal demand for an extraordinary general meeting of shareholders.

Norwegian businessman Christen Ager-Hanssen, whose investment vehicle Custos now owns 20.01pc of JP, issued the EGM call via his lawyers yesterday afternoon.

He is demanding the removal of JP chairman Camilla Rhodes and non-executive director Mike Butterworth and their replacement by former Scottish First Minister Alex Salmond and former Local World boss Steve Auckland.

He has also launched an extraordinary attack on current JP chief executive Ashley Highfield, accusing him in a Tweet of ‘abuse  of power’ by ‘using JP and its proud titles to fight personal battles.’

It is unclear what Mr Ager-Hanssen was referring to in the Tweet, but it came on the same day that Scotsman editor Frank O’Donnell launched a withering attack on Mr Salmond over the takeover plot.

In a strongly-worded editorial on Friday, Frank questioned the former Scottish Nationalist Party leader’s suitability to run a newspaper business – and his commitment to editorial independence.

Mr Highfield, who has run JP since 2011, faces the loss of his job if Mr Ager-Hanssen’s coup succeeds, with Mr Auckland slated as his potential successor.

Johnston Press confirmed the latest developments in a statement to the Stock Exchange this morning.

It read: “Johnston Press announces that it has received a letter from Custos Group AS, a shareholder holding in excess of five per cent. of the paid up capital of the Company, requisitioning a general meeting of the Company’s shareholders (the “Requisition”).

“The Requisition proposes resolutions that Camilla Rhodes and Michael Butterworth be removed as directors of the Company, and that Alexander Salmond and Steve Auckland be appointed as non-executive directors of the Company. The Requisition also proposes that any person appointed as a director of the Company since November 6, 2017 (being the date of the Requisition) be removed as a director of the Company.

“The Johnston Press Board is consulting with its advisers and will update its shareholders with regard to the timing of the General Meeting in due course.

“Shareholders are advised to take no action at this time. Further announcements will be made as appropriate.

Replacing the two board members would not give Mr Ager-Hanssen immediate control of Johnston Press, but it could lead to further changes, for instance by changing the balance of the company’s nominations committee.

The Norwegian appeared to step back from a full takeover after it emerged that if a majority of board members were replaced, the company’s £220m debt would become repayable immediately.

Mr Ager-Hanssen told the Telegraph: “We are taking a step-by-step approach now. We want to get our people on the board and see what they have done to Johnston Press.”

Johnston Press will now have 21 days to send shareholders notice of an EGM, with the meeting held within a further 28 days.

With Mr Ager-Hanssen needing the support of at least 50pc of shareholders, the attitude of other institutional investors will be critical in determining the outcome.

These include Malaysian businessman Ananda Krishnan Tatparanandam with 10.63pc of the company, veteran local newspaper entrepreneur Sir Ray Tindle with 6pc, hedge fund Crystal Amber with 10.48pc, and two asset management firms which together own just over 14pc of the business.

A source close to JP said: “The company is in the midst of a complex and important refinancing and we have the momentum with the established team to ensure further progress with the strategic review and ensure a good outcome.

“Despite dozens of tweets and interviews, Custos has not yet produced a coherent strategy or plan.”