Former Prime Minister David Cameron has been in the news for his "lobbying" of the government. But what does that mean?
What is lobbying?
Lobbying is when individuals, businesses, trade unions, groups or charities try to get a government to change its policies. "Political persuasion" might be a better term.
How does it happen?
Lobbyists make their case to ministers, MPs or officials. They can write, email, text, phone, video call or turn up in person in Parliament to do it, although the latter hasn't happened over the past year due to Covid-19 restrictions.
Does lobbying work?
Not always. Changing politicians' minds can take a long time. That's why organisations and firms often hire professional lobbyists to make arguments on their behalf. Some of these are former politicians themselves and "know the game" - that is, who's who and where to find them.
But it's important to re-emphasise that individual citizens - unpaid - can also lobby politicians about issues that are important to them. Anyone can be a lobbyist, in other words.
So is the system fair?
Supporters say professional lobbying is a vital and valid part of democracy - that it stimulates debate and keeps politicians in touch with the latest developments in areas like science and business.
But critics argue that the current system is open to corruption and that wealthy interests - the ones who can afford professionals to make their case - have an unfair advantage.
What are the rules?
Ministers and top civil servants are effectively banned from lobbying their former colleagues for two years after leaving government. Lobbyists also have to join a register, which was set up by David Cameron as prime minister.
Mr Cameron, who left Downing Street in 2016 and started work as an adviser for Greensill Capital in 2018, says he broke no rules. But he has faced criticism over the apparent ease with which he contacted current ministers, including texting Chancellor Rishi Sunak on behalf of the company.
Under the current rules, partly drawn up by Mr Cameron when he was in Downing Street, he did not need to register as a lobbyist because he was working as an "in-house" adviser to Greensill, rather than being employed by a company specifically dealing in lobbying.
Is anything changing?
Following the disclosures about Mr Cameron's work, the government has set up a review of lobbying, led by a lawyer, which is due to report back by the end of June. Prime Minister Boris Johnson is promising this will be given free rein to ask questions.
Labour is calling instead for a "full" inquiry by MPs from different parties - with sessions to be held in public, but that is not now going to happen after it was voted down by Conservative MPs.
Why is it called lobbying?
It started long ago when members of the public turned up in Parliament's lobby areas to let MPs know what needed to change.
It's harder to get into that part of the building than it used to be because of tougher security, so meetings are just as likely to take place elsewhere, such as over dinner, in MPs' constituencies or via the phone.