By Maiya Keidan and Rahul B

LONDON/BENGALURU (Reuters) - Activist investor Custos Group is considering its next steps after discovering a clause in a bondholder deal that hindered its attempt to oust Johnston Press top management.

Custos Group, run by fund manager Christen Ager-Hanssen, had lined up four directors to be nominated to the Johnston Press board before finding out this weekend it would not be possible to proceed due to a so-called "dead hand proxy put".

The proxy inserted into Johnston Press's bondholder agreements when it refinanced its 220 million pound ($290 million) debt pile three years ago means that only the existing board can approve a new director.

"We are now considering all type of options we have; of course we will talk to all stakeholders in the company," said Ager-Hanssen, who is the second-largest shareholder in Johnston Press with a 12.57 percent stake. "We don't think the board or the CEO have done anything to build up the company."

He added that he would delay his plan to seek a management rejig at the company.

Shares in Johnston Press, which publishes British dailies such as the Scotsman and i newspaper, fell more than 18 percent by midsession on Monday after The Telegraph reported on Saturday that Ager-Hanssen had been forced to delay a call for a shareholders' meeting.

In August, Johnston Press reported a 30.9 percent fall in half-year adjusted pretax profit and warned trading conditions for regional newspapers in the UK continue to be difficult.

The newspaper industry has been hard hit in recent years as advertisers have followed readers to online platforms, forcing print publishers, such as Trinity Mirror and Daily Mail and General Trust, to cut costs drastically.

Johnston Press had a net debt of 203.9 million pounds at Dec. 31, according to its latest annual report.

Last year, Crystal Amber Fund, an activist investor and largest shareholder in Johnston Press, had offered help to the company to avoid a poor debt restructuring deal. [nL3N1C535Q]

"Despite the speculation and press comment, at the moment, there’s no proposal from Custos," Crystal Amber fund manager Richard Bernstein told Reuters. "If and when there is, we’ll assess it."

In an emailed statement, Ager-Hanssen told Reuters: "The board is doing no more than rearranging the deckchairs on the Titanic. They literally have no clue as to how create shareholder value." He declined to say what other options he was considering.

Johnston Press was not immediately available for comment. Its shares were trading down 18.1 percent at 14.08p by 1220 GMT.

($1 = 0.7592 pounds)

(Reporting by Radhika Rukmangadhan and Rahul B in Bengaluru, with Maiya Keidan in London; Editing by David Holmes)