One of the UK’s top fund managers is to boycott the stock market float of the meal delivery firm Deliveroo next month, amid growing disquiet in the City over the company’s treatment of delivery workers.

Aviva Investors said on Wednesday it had turned down the chance to invest in Deliveroo’s £9bn initial public offering. Aberdeen Standard, another of the UK’s biggest investors, has also expressed concerns about Deliveroo’s employment practices, the Guardian understands.

David Cumming, the chief investment officer for equities at Aviva Investors, which is part of the UK’s largest insurance company, said there was a combination of investment risk and social issues that affected its decision on whether to buy shares or not.