Boris Johnson personally promised Sir James Dyson he would “fix” an issue over the tax status of his employees after being directly lobbied by the entrepreneur, it has been reported.

Labour has claimed there is “evidence” the Prime Minister may have breached the ministerial code with the exchanges regarding ventilators at the height of the coronavirus crisis, which were revealed by the BBC.

It comes amid intense controversy at Westminster over lobbying following the disclosures of David Cameron’s activities on behalf of the failed finance firm, Greensill Capital.

But what is the ministerial code and what are some of the criticisms of it?

– What is the ministerial code?

The ministerial code is a set of rules and principles outlining the standards of conduct for government ministers.

It requires ministers to disclose their interests in detail, while the rules state that ministers should have an official present when discussing government business.

If a minister finds themselves discussing government business without an official present, such as at a social occasion or on holiday, they should report pack to their department as quickly as possible, according to the code.

– Is this different to the Nolan principles?

The ministerial code says that ministers are expected to abide by the Seven Principles Of Public Life, also know as the Nolan principles, which is the basis of the ethical standards expected of public office holders.

– Does the ministerial code need to be updated?

Former prime minister Tony Blair, in Downing Street from 1997 to 2007, said he did not have a mobile phone while he was in office – highlighting the way communication in Whitehall has changed in recent years.

Tim Durrant, associate director at the Institute for Government (IfG), told the PA news agency: “It (the ministerial code) does need to be updated to reflect how people communicate now.

“Ministers are supposed to declare all of their meetings, but what is a meeting in the pandemic world – does that include Zoom calls? Even if it does, lots of government conversations happen by email, by text message, by WhatsApp.

“They should absolutely be included in the transparency publications that ministers have to provide, and they are not currently.”

– How is the ministerial code enforced?

Where a breach of the ministerial code is alleged, the prime minister decides whether an investigation should be called, which has raised concerns about how independent the process is.

Potential breaches of the code are investigated through an independent adviser on ministerial interests, and following this, the prime minister will then decide whether a breach has occurred.

– Who is the current independent adviser?

The post of independent adviser on ministerial interests has been empty since November, when Sir Alex Allan resigned after Mr Johnson stood by Priti Patel in a bullying row surrounding the Home Secretary.

Mr Durrant, from IfG, suggests that if a new independent adviser is appointed, they should be given power to conduct an investigation on their own if they believe an issue warrants it.