Former prime minister courted senior Abu Dhabi official he had hosted in No 10 in apparent breach of rules

In early 2024, a vape lobbyist, a Vote Leave campaigner and a Vienna banker set out to persuade the rulers of an oil-rich Gulf emirate to give them a billion dollars. For the plan to work, leaked files suggest, they needed a frontman who had some pull with the sheikhs. So they hired Boris Johnson.

His time as the UK’s prime minister had ended less than two years earlier and he had left parliament. But Johnson retained relationships cultivated during his time in power. The Boris Files, a cache of documents seen by the Guardian, suggest he has sought to harness these relationships for self-enrichment.

The leaked files raise questions about whether Johnson broke ethics rules by lobbying a top foreign official to “secure his patronage” for a business venture that stood to make him millions.

In need of funding, Bia Advisory, a largely unknown “climate finance solutions” venture, hired the ex-PM as its “principal adviser”. The idea was to deploy Johnson – charismatic and well connected after his years as mayor of London, foreign secretary and prime minister – to open doors in the desert.