Ian Clarke spent six months working 21-hour days around his regular job, collating data and interviews for a report alleging racism at HSBC, where he had worked for 15 years.

The 36-year-old spoke to 100 current and former employees of the bank who relayed their own careers, many claiming to have experienced racism at the UK lender. What started out as a small presentation swelled to a 48-page document, dubbed Project Speak Up, as every claim and data point was scrutinised and questioned by those around him, he said.