If there is one issue that highlights the gulf between government and opposition, it is the lobbying industry. Promises to bring in tougher regulation are easy for an opposition to make but harder to implement. And the way politicians behave when they move from opposition to power needs to change. There was a classic case in 1997 when Derek Draper, a lobbyist and former aide to Peter Mandelson, boasted that he knew the "17 people who count" in the Blair government.
After he succeeded Tony Blair in 2007, Gordon Brown hinted at his support for a statutory register of lobbyists. But Cabinet Office ministers struggled to make it work.
Three months before last year's election, David Cameron described commercial lobbying as the "next big scandal waiting to happen". He said it had "tainted our politics for too long" and "exposes the far-too-cosy relationship between politics, government, business and money".
Tough words, but not yet matched by action. The Coalition agreed to bring in a statutory register. But took the affair that led to the resignation of Liam Fox as Defence Secretary in October to push the issue back to the top of the agenda. His friend and adviser Adam Werritty was not a lobbyist but his globe-trotting was funded by Conservative Party donors and businessmen.
Firm proposals on a register were promised by November but failed to materialise. There appears to be a wrangle going in Whitehall over how transparent ministers and officials should be in listing their contacts with lobbyists. And charities have warned of unintended consequences that could impede their work in informing government policy. One man's lobbyist is another man's standard-bearer for a good cause. Most ministers agree industry has a role, that it would be counter-productive if legislators were denied direct contact with experts in their field.
There can also be problems when politicians leave office – "revolving door" syndrome when former ministers become lobbyists. The former Labour cabinet ministers Geoff Hoon and Stephen Byers were banned from the Commons for five years and two years respectively last year after being caught on camera touting for consultancy business in an undercover sting by Channel 4's Dispatches and The Sunday Times.
Over the years, several efforts to curb the influence of lobbyists have been made but have had limited impact. Ministers complain the firms are an evasive target. After a clampdown on lobbyists securing House of Commons passes by working for MPs, allowing them access to many parts of the Palace of Westminster, several merely moved house to the Lords. The political parties may all talk tough about the influence of lobbyists but are quite happy to take their money.
In recent years, the annual party conference season has seen a growth in the number of lobbyists attending. This autumn less than a quarter of the 30,000 people who attended the Conservative, Labour and Liberal Democrat conferences were party members, leading to complaints that the events had become glorified "trade fairs". Ministers were told to "drop by" stalls in the exhibition hall. Power attracts money: the Tory conference is believed to have made a £2m profit.
Caught on camera: top lobbyists boasting how they influence the
* The Sting: The fake 'Asimov Group' meets Bell Pottinger
* The Transcript: 'David Cameron raised it with the Chinese Prime Minister'
* We wrote Sri Lankan President's civil war speech, say lobbyists
* Vicious dictatorship which Bell Pottinger was prepared to do business with
* Oliver Wright: Vested interests are entitled to argue their case, but it must be in the open
* Andrew Grice: Plenty of talk about cracking down on lobbying – but still there's no action
* Leading article: Evidence of a lobbying industry out of control