Mike Ashley is tightening his grip on the management of Sports Direct International (SDI), the embattled British sports retailer, taking over as chief executive after the resignation of Dave Forsey last week.

Forsey's departure comes after several months of intense pressure on SDI, the owner of Karrimor and Gelert as well as the Field & Trek outdoor retail banner. Earlier this year the retailer had to revise its profit forecast downward, investors have voiced concerns about governance at the company, and it has come under scrutiny over working conditions at its huge warehouse in Shirebrook. At the group's annual general meeting (AGM) earlier this month, a majority of independent shareholders voted against the re-election of Keith Hellawell as chairman of SDI.

Forsey quit as a chief executive and director, and Ashley's appointment last week was with immediate effect, but Forsey agreed to help with the transition. Forsey has accompanied the rise of Sports Direct for more than three decades, starting as a shop assistant when he was a teenager. Ashley said in the statement about Forsey's resignation that he felt as if he had lost his right arm.

However, Forsey has been criticized in a report by SDI's legal advisers for failing to flag the issues at the warehouse with sufficient urgency. Ashley admitted at a parliamentary committee hearing in June that some workers at the warehouse had temporarily been paid less than the minimum wage because they were held up by security checks, and the retailer was negotiating compensation. In a preliminary report compiled by Reynolds Porter Chamberlain (RPC) about working conditions at SDI and published by the group before its AGM, Forsey was described as the person ultimately responsible for some of group's issues in this area.

Forsey agreed already in June to forfeit a share bonus due next year, which would have been worth about £3.6 million (€4.15m-$4.66m). He otherwise received a salary of £150,000 (€172,783-$194,331) that is relatively low for listed companies of SDI's magnitude.

Many decisions at Sports Direct in the last years have been influenced by group strategy discussions held in a pub near the group's head office, and Ashley was widely perceived as the driving force behind the group's expansion, but until last week he was SDI's executive deputy chairman. His appointment as chief executive has led to a jump in the price of SDI shares, which has been pummeled in previous months. Then again, some questions were raised about Ashley's management of the company, when he admitted himself at the parliamentary committee hearing that SDI was outgrowing him.

The change in leadership comes after a raft of concessions by SDI about working conditions and corporate governance. Just before the AGM, the company said that workers on controversial zero-hour contracts would be offered jobs with a guaranteed minimum of 12 hours per week. The group pledged to reform the infamous “six strikes” policy that could see workers reprimanded and potentially sacked for minor issues. Then it announced that an employee representative was to be elected to the board. After the AGM, the group also caved in to shareholder pressure and agreed to have a review on corporate governance supervised by an independent party – and not RPC.

Separately, SDI announced that Karen Byers, head of retail, has become global head of operations, while Sean Nevitt, the head of buying, has been elevated to global head of commercial activities.