Trade unions and charities could be forced to sign up to a new statutory register of parliamentary lobbyists aimed at cleaning up politics, the Government announced today.

Lobbyists who deliberately failed to comply with the anti-sleaze rules would face up to two years in prison under the proposals published by the Cabinet Office.

Mark Harper, Minister for Political and Constitutional Reform, launched a 12-week consultation on how the register should work and legislation is expected to be introduced in the next session of Parliament.

"Lobbying has an important role in the policy-making process, ensuring that ministers and senior officials hear a full range of views from those who will be affected by Government decisions," he said.

"But it must be conducted in a transparent and open way.

"We already publish an unprecedented amount of information about who ministers and senior officials meet.

"However, it's not always possible to understand the significance of these meetings, because it's not always obvious who the people ministers and officials meet represent.

"That's why the Government wants a register that will bring more transparency to the lobbying process and we would welcome the views of the public and the lobbying industry on this consultation document."

The long-delayed proposals come in the wake of revelations in The Independent about the extent of the influence claimed by lobbyists.

Officials said today that in-house lobbyists will not be included in the register because any meetings they hold with ministers would appear in existing records and their interests would be obvious.

Instead, Government is following Australia's lead by targeting "those who seek to influence or change government policy on behalf of a third party".

It is consulting on whether that definition should extend to trade unions, charities and thinktanks.

Under the proposals, the register would hold the name of the individual lobbyist and whether they are a former minister or senior civil servant.

Detailed financial information would not be included as it would "provide too great an administrative burden" but ministers are looking at "whether it would be useful" to give an idea of how much each client pays.

A Downing Street spokeswoman said: "The Government has done an awful lot to increase transparency, and transparency generally is what will help to raise people's confidence in politics and the political system.

"This is another step in that, but it is important we get it right. We want to seek the views of people on this issue, and we look forward to hearing what people have to say on this issue."

The Government said it "hopes" the lobbying industry will "embrace" the reforms, making the process "largely self-regulating".

But it plans to introduce sanctions for non-compliance and has pegged them against the penalties levelled at companies who fail to file their accounts.

That means fines up up to £5,000 for missing deadlines or higher fines and a maximum two year jail term for knowingly making misleading statements.

It comes after widespread criticism of the access and influence lobbyists have over senior politicians.

Executives of one firm, including an ex-Tory politician, were recently secretly taped saying they could directly influence Prime Minister David Cameron and senior ministers on behalf of private sector clients.

Downing Street dismissed that as "simply untrue" but the case further fuelled demands for a register following a string of scandals over recent years.

In 2010 three former Labour ministers were stripped of parliamentary passes after they breached lobbying rules and the House of Lords was rocked by a "cash for amendments" scandal.

Jon McLeod, chairman of Weber Shandwick, said: "We have long argued for statutory regulation as the best means of assuring public confidence in the public affairs industry.

"We will study the proposals in detail and continue to argue for registration of all lobbyists, whether in-house or in private practice."

RMT general secretary Bob Crow said: "The idea that trade unions, representing millions of workers up and down the country, should be bracketed in with the chancers and shmoozers from the shadowy world of political lobbying is a gross insult to men and women fighting for a fair deal in the workplace.

"This is just another blatant ConDem attack on the trade union movement and shows complete and utter contempt for the role we play in protecting working people from the savagery of casino capitalism."

In 1997, Duffy faced more murder charges after two police officers on foot patrol were shot around midday in the centre of Lurgan.

Constable John Graham and Reserve Constable David Johnston were both in their 30s and married with young children.

Duffy was arrested by police who claimed a witness linked him to the killing.

But the case collapsed after other witnesses came forward in defence of Duffy.