The activist investor targeting Barclays has raised the stakes in its battle to boost returns as it revealed it is trying boot out current chair John Macfarlane.
Sherborne Investors, the vehicle of renowned activist Edward Bramson, said it wants to influence the "search process for and mandate of a new chairman" in an announcement to the market.
The announcement sets the activist on collision course with City veteran Macfarlane only three years after he took the helm at the board of one of the UK's biggest banks.
Bramson targeted Barclays in the spring as the latest candidate for pressure after it built up a stake of more than five per cent, allowing him to call for votes at shareholder meetings.
The intervention in the bank is focusing on "capital allocation, quality of earnings, capital adequacy, cost structure, and the search process for and mandate of a new chairman", the listed management company said in half-yearly results.
Barclays informed the market in March that Sherborne had built up a stake, and has since focused on defending its business. It was aided in this effort by relatively strong second-quarter results, although debate still rages around the bank's investment bank, which some shareholders believe is not pulling its weight.
The Sherborne statement made no explicit reference to the investment bank, although a focus on capital allocation would likely focus on focusing the bank's financial firepower on more profitable parts of the business.
Barclays has been investing in its markets business, as well as adding to its US cards operations and recently announcing a new 2,500-person campus in Glasgow.
"The investment manager believes that addressing these matters could improve Barclays' financial strength and its long-term competitive position, leading to an increase in shareholder value in line with the investment manager's customary return objectives," Sherborne's statement said.
Macfarlane told investors at the bank's last annual meeting in May that they are "not getting rid of me yet". He joined Barclays in April 2015, after previously chairing insurance giant Aviva and serving on the boards of Royal Bank of Scotland and Australia and New Zealand Banking Group.
Sherborne gave Barclays no guidance on a timeline for its intervention, saying it will stay invested "as long as it appears to be appropriate to do so".
At the end of June it held 87m Barclays shares, with a market value of £1.6bn, according to S&P Global Market Intelligence.