The board room battle at Stobart Group is continuing to escalate and could move to the High Court as shareholders prepare to vote on the future of its chairman.

According to reports, Stobart Group has filed a legal claim with the Commercial High Court against executive director and former chief executive Andrew Tinkler along with William Stobart, former chief operating officer, William Stobart, to recover an unspecified amount from them in relation to a tax scheme they set up as part of a related-party transaction in 2008.

In a fresh twist over the weekend, Mr Tinkler has said he will “issue proceedings” against five fellow board members if they fail to retract a statement made in a regulatory statement that he says contained "false and defamatory material about me”.

According to the Financial Times, the five directors cited are chairman Iain Ferguson, chief executive Warwick Brady and non-executive directors Andrew Wood, John Coombs and Richard Laycock.

Mr Tinkler has been at the centre of a public spat with Stobart Group bosses to remove him, citing serious differences over the future strategy of the infrastructure and support services company.

He wrote to Stobart Group shareholders on Friday urging them to vote against the re-election of Mr Ferguson.

In the letter – quoted by the Financial Times – Mr Tinkler criticised “the public mud-slinging in which some of my fellow directors have seen fit to engage without any regard to the waste of the company’s resources involved or the impact on employees, customers and suppliers”.

He also claimed that more than 80 per cent of Stobart Group’s executive leadership team were also in favour of Mr Ferguson being replaced as chairman by Edinburgh Woollen Mill tycoon Philip Day.

The company, which owns and operates Carlisle Lake District Airport, has received an official request from a trio of shareholders including its executive director and former chief executive Andrew Tinkler, to nominate the Edinburgh Woollen Mill tycoon as a board director.

If passed, the trio of shareholders – which hold more than 33 per cent of the company's voting capital and includes Allan Jenkinson and funds acting through Woodford Investment Management Limited – then want the Stobart Group board to nominate Mr Day as chairman and replace Mr Ferguson.

The decision on whether to re-elect Mr Ferguson will take place at the group’s annual general meeting in Guernsey on Friday, July 6.

However, it is unclear whether a vote to elect Mr Day to the board will take place before the AGM, with a Stobart Group spokesman saying the date of a separate meeting to consider the nomination was still to be confirmed.

In turn Stobart Group are urging shareholders to re-elect the current chairman, accusing Mr Tinkler of destabilising the group “at this crucial time for the business”.