Warnings of threats to democracy should be sparingly issued: they contain the risk of undermining an argument through hyperbole, of making us numb to genuine menaces. But be under no illusions: the Government’s catchily titled Transparency of Lobbying, Non-Party Campaigning and Trade Union Administration Bill is an audacious stab at many of our hard-won democratic freedoms. It does nothing to take on the corporate lobbyists who give Big Money its shady political clout, but it threatens to stifle the voices of charities, campaigners, trade unions and even blogs; to shut down rallies and demonstrations; and to prevent groups such as Hope Not Hate from taking on the poison of organised racism.

Here’s what has happened. David Cameron once warned that lobbying was “the next big scandal waiting to happen”. It seemed prescient when City banker-turned-Tory party treasurer Peter Cruddas was the victim of a Sunday Times sting operation that seemed to expose him suggesting money could buy access to the Tory leadership. As it turned out, the paper had defamed him and had to cough up £180,000 in damages. But nonetheless, the Tories did what they have proven so adept at doing: turning a crisis of their own into a crisis for their enemies, just as they transformed a financial crisis into a public spending crisis.

There is no question that British democracy is at the mercy of wealthy and corporate interests. Tony Blair’s attempts to rid Labour of its dependence on trade union members’ donations in favour of private benefactors led to the first time a prime minister has been formally questioned in No 10 in the so-called cash-for-honours scandal. The indefensible undemocratic sham that is the House of Lords means that wealthy establishment figures, many of whom have donated generously to political parties, are parachuted on to the red benches. Hedge fund managers, bankers, asset strippers and legal loan sharks bankroll Cameron’s Conservative Party. The former Tory health secretary Andrew Lansley received £21,000 worth of funding for his personal office from John Nash, the former chairman of Care UK, a private health company that stands to benefit from the privatisation of the NHS. Cameron’s key adviser Lynton Crosby is a lobbyist for big tobacco, private healthcare companies and elements of the Syrian rebels. Major banks and businesses casually issue economic blackmail – both privately and publicly – when elected governments propose policies that displease them. And then there’s the army of shadowy corporate lobbyists, whispering in the ears of ministers, special advisers and civil servants.

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But the “lobbying” Bill – surely one of the most badly written pieces of legislation put to the Commons in recent times – deals with none of these scandals. Consultant lobbyists operating on behalf of a third party will have to be placed on a register. That’s easy to get around: big business will simply take their lobbyists in-house, leading to even less transparency.

Part two of the Bill, which governs “non-party campaigning, etc”, will transform what is meant by “election campaigning”. Currently, all organisations spending more than £10,000 on campaigning in England and £5,000 in Scotland or Wales must register with the Electoral Commission; that will drop to £5,000 and £2,000 respectively. As things stand, registered charities and other campaigning organisations can spend up to £989,000 a year before a general election; not only will this be slashed to £390,000, it now includes everything from staff costs to transport, market research to public meetings.

The defenders of this Bill argue that it will stop the importing of US-style political action committees (PACs), which are vehicles for the outright capturing of politics by the wealthy elite. But that is to target a problem that does not even exist, because current law prevents this from happening. Instead, this vaguely worded Bill targets anything which may impact on an election, whether or not that is the intention, leaving it up to the Electoral Commission to decide. In practice, that could mean everything that can possibly be campaigned about: Shelter calling for more social housing or a cancer charity fighting for more resources.

Because the Bill is so open to interpretation, it will have a chilling effect. Trustees of charities will fear anything that invites criminal investigation, shutting down scrutiny of government or campaigns for changes in policy. It will entangle organisations in a bureaucratic nightmare, forcing them to account for all of their spending. No wonder the British Medical Association said that “if the Bill is passed, its impact could be deeply disturbing, especially as it raises concerns about what this would mean for freedom of expression”.

The implications are frightening for any genuine democrat. The TUC suggests that it could make organising its 2014 annual congress a criminal offence, as well as prevent it from holding a national demonstration in election year. It is difficult, then, to quibble with its assessment that this is “an outrageous attack on freedom of speech worthy of an authoritarian dictatorship”. And then there’s Hope Not Hate, which has played a pivotal role in taking on the scourge of political racism: while its spending would be capped, the BNP would be allowed to spend anything up to nearly £19m. Political blogs such as ConservativeHome and LabourList could be included, too, since they are campaigning entities that attempt to impact the outcome of an election.

The legislation means yet further state regulation of trade unions, which – as Tony Blair once boasted – suffer laws that are “the most restrictive in the Western world”. A Certification Officer will be imposed on them with access to their register of members’ names and details, including correspondence with the union. It is unclear for what purpose exactly, though: unions already have to present meticulously accurate membership records during industrial action, because employers can otherwise shut down strikes through the courts. One theory is that it will be used to cause havoc in internal Labour Party selections: a complaint from the Conservatives or Lib Dems about a candidate could trigger an inquiry from the Certification Officer about how they were selected.

What government has launched such a shameless assault on our democracy in recent times? Privately, Lib Dem MPs have talked of the need to prevent student organisations from tarnishing candidates, thus securing a Labour win: damning evidence that they want to shut down scrutiny of their many broken promises during their shabby term in office. Voltaire once acidly remarked that the Holy Roman Empire “was neither holy, nor Roman, nor an empire”; the Liberal Democrats have shown that they are neither liberal nor democrats. But our rights and freedoms were won through the struggle and sacrifice of our ancestors. It is not for us to allow them to be casually tossed to one side. This Bill – this brazen insult to democracy – must be defeated, crushed, obliterated. Time is running out.