Edward Bramson has urged shareholders to give him a seat on the board of Electra Private Equity.
Bramson (pictured) has requisitioned the £1.3 billion trust to call an extraordinary general meeting to give investors the opportunity to vote on raft of resolutions he proposes.
The call, which was done through his investment vehicle Sherborne, wants both Bramson and former Sherborne chair Ian Brindle to be handed seats on the Electra board.
At the same time it demands the removal of former Hamley's chief executive Geoffrey Cullinan, who joined the Electra board in 2011 and serves as chair of its management engagement committee.
Cullinan has decades' experience in private equity, including an eight-year spell from 1997 as a director of Bain & Company, where he was founder and leader of its private equity business and in Europe. He remains an adviser to the firm.
Prior to this he was managing partner of OC&C Strategy Consultants, which he co-founded in 1986.
If shareholders vote in favour of the recommendations, Bramson intends to conduct a strategic review at Electra aimed at improving returns for investors.
'Sherborne Investors has also informed the board of directors of the company that it intends to communicate in due course with shareholders of Electra to describe the substantial opportunities that it believes a strategic review would provide for all shareholders in Electra to increase the value of their holdings,' Sherborne told the stockmarket.
In a separate stockmarket statement Electra defended its strategy. 'The board has always listened, and will continue to listen, to the views of shareholders consistent with enhancing long-term shareholder value,' it said.
'The board of Electra actively keeps the company's strategy under regular review, is of the opinion that the current strategy has delivered superior long-term returns for all shareholders and sees no reason to deviate from this successful strategy.'
Bramson first bought into the trust in February and has gone on the build a 19% stake.
His formal demand for a board seat comes after Electra turned down an initial approach from the activist at the end of July to implement the changes.
At the time the company said: 'The board of Electra has a long-standing policy of being comprised wholly of independent non-executive directors. Mr Bramson, representing a c.19% shareholder in the company, would not be independent.
'The company's consistently superior performance over the long term provides clear evidence to support this policy of complete independence.'
It highlighted the trust's long term performance, which has seen its share return 268% over the last 10 years versus a 129% rise in the FTSE All Share.
Electra is a split capital trust founded in 1976, making it one of the UK's oldest private equity trusts. It's ordinary income shares sit on an 8.4% discount.
In the second quarter it invested £124 million, including £81 million in Ogier Fiduciary Services and £33 million in Innovia.
It outperformed in this period, with shares up 3% versus the 2% rise in the FTSE All Share.
Over 12 months to the end of June shares increased by 21% versus 13% in the benchmark, thanks in part to interest in Sherborne's stake building.
In the third quarter the firm has made a number of new investments, including the acquisition of DiGiCo and a further £20 million invested in Southview and Manor leisure parks.
Commenting the recent performance, chair Roger Yates said: 'Recent performance continues to be strong with the investments made over the past two years already starting to generate returns.
He added: 'Making full use of its flexible investment strategy, Electra Partners has been busy actively pursuing value creation strategies across the portfolio and has completed a number of attractive investments in the period.
'Electra is very well positioned to continue its record of delivering consistently superior long-term returns for its shareholders.'
This is not Bramson's first attempt to shake things up in the funds world.
Last August he stood down as chair of F&C Asset Management two years after leading a boardroom coup at the asset manager.
Under his command he repositioned the business, which saw a number of job go in a bid to cut cost from the balance sheet.