The advisory firm led by Andy Burnham’s incoming chief of staff counted BP, Amazon, Jaguar Land Rover and Uber among its clients, transparency records reveal.

Burnham is facing unease within Labour over the lobbying links of James Purnell, a longstanding friend and former cabinet minister who was most recently chief executive of Flint Global.

Flint Global does not publish a list of clients but is a registered lobbyist, with two entries in the past five years showing it had contact with government ministers or officials on behalf of companies.

The company says it advises international businesses and investors on policy, politics, regulation and competition.

Until recently, Purnell held shares in the firm, which is owned through a holding company based in Jersey, making its structure opaque. It is majority owned by the private equity firm Cinven.

Despite not publishing who it works for in the UK, a list of its clients from last year is registered on the transparency register of the EU, which includes Google, Microsoft and the mining firm Glencore. Apple appeared to be its biggest client in Europe, paying the company more than €1m in the last year for which data is available.

It is understood Purnell has given up his shares, will no longer have a connection to the firm, and has no access to Flint emails or systems with immediate effect. A Burnham team spokesperson said: “James has left Flint. He will have no ongoing financial interest in the company of any kind.” They said any future conflicts of interest would be appropriately managed.

One of the big issues in Burnham’s domestic in-tray will be whether to press on with Starmer’s greater regulation of big tech and AI including the social media ban and attempts to prevent misinformation circulating online.

Burnham’s choice of Purnell has already caused some consternation among many of his supporters on the Labour left, who fear it has echoes of Keir Starmer’s decision to appoint key Blairites such as Peter Mandelson as US ambassador and Tim Allan director of communications – both of whom still had stakes in lobbying firms that they did not give up while in post.

One Burnham-supporting MP on the left said they felt the appointment was a “very bad sign that he is not thinking things through enough”.

“I am deeply worried about this,” said another senior adviser. “I am worried this does not look like change and it will lead to the same scandals that have hamstrung Keir. He is being convinced to dilute himself to placate the rightwing forces that will never support or agree with him.”

However, others in Labour have welcomed the appointment of Purnell as a sign that Burnham will not turn away from business and intends to oversee a broad coalition within the party.

Zack Polanski, the Green party leader in England and Wales, asked why the Labour government appeared to be “so keen on bringing in corporate lobbyists into the heart of Downing Street”. “This is starting to feel like a bit of a Blair and Starmer tribute act, with Labour Together’s Josh Simons also expected to have a senior role,” he said.

“So there can be no suspicion that James Purnell, a tireless campaigner for welfare cuts, is putting the interests of his clients above those of the people he’s supposed to serve, a full list of Flint Global’s clients must be published.”

A Flint spokesperson said Purnell had resigned and in the meantime he had “recused himself from all client activity and has no ongoing financial interest in the company of any kind”. “James’s decision to join Burnham’s team is entirely his own, and one we fully respect,” they added.

In a message to staff, after a media report about his appointment, Purnell said: “I am still finalising details with the Flint board but the story is basically correct and I am likely to be leaving shortly …

“We will make sure there is plenty of time for handover over the next few days and we will hold a team meeting as soon as possible. Flint is a wonderful organisation and culture. I’ve learned a huge amount and look forward to keeping in touch. I will miss you all and look forward to watching you continue to flourish.”