The act, which also created ORCL, Westminster's statutory lobbying register, tightened regulations around campaigning activities in the run-up to elections by groups other than candidates for election and political parties.
However, these regulations have been criticised as unnecessarily onerous and complex, and are seen by some in the charity sector as a deliberate effort to stymie its campaigning and advocacy voice.
Campaign Collective's report, 'Freedom to campaign: a handy guide to what you CAN do under the Lobbying Act', notes that almost half of charity communicators don't understand the act's rules, and says there has been a "chilling effect", with a fifth of charities campaigning less than they did prior to it coming into law.
Nancy Platts, a consultant at the agency who previously worked in the office of Labour leader Jeremy Corbyn, said she had seen a "marked decrease in the number of small charities and campaigners approach me" when running as a candidate in the 2015 general election, versus her previous run for office in 2010.
"A charity can carry out campaigning and political activity... [including] raising public support for change and seeking to influence political parties or independent candidates, decision-makers, politicians or public servant," the guide says, but adds: "Political campaigning must not be the continuing and sole activity of the charity."
Elsewhere, it suggests: "Don’t be party political, don’t reciprocate support and don’t publicly shame politicians or political parties that don’t support you."
The Campaign Collective guide simplifies the more than 100 pages of official Electoral Commission guidance on the act into 10 pages, although it makes clear that it does not constitute "formal legal advice".
Platts said: "The Freedom to Campaign Guide is designed to be a simple, plain-English interpretation of more than 104 pages of official guidance which small charities and campaigners could not be expected to wade through."
The agency, which gives profits to charity and social projects, was set up in 2016 by Simon Francis, who is also chair of the PRCA charity and not-for-profit group, in which guise he has previously criticised the advice given to charities by the Electoral Commission and the Charity Commission.