The Conservatives’ election manifesto is being written by a lobbyist for the fracking company Cuadrilla and major internet companies such as Amazon and Facebook, raising concerns about whether her paying clients could influence the party’s policies.

Rachel Wolf is drawing up the Conservatives’ platform for the general election while continuing to work as a partner at Public First, a business which lobbies ministers on behalf of the shale gas industry. Cuadrilla is facing a battle to keep its fracking projects on track in the UK at a time when public opinion is moving against the extraction of shale gas, with the Labour party threatening to ban the practice altogether.

Her company also represents the Internet Association, the trade body for major tech companies including Uber, Twitter, Facebook, Google, Airbnb, Microsoft and Amazon. The organisation is attempting to influence the government’s policies on online harms, the regulation of social media and taxes on digital companies – all of which are likely to feature in some form in the Conservative manifesto.

Rachel Wolf, pictured in 2010. Photograph: Linda Nylind/The Guardian

Wolf, a former aide to Michael Gove and a pioneer of the free school movement, co-founded Public First with her husband James Frayne in 2016 and it has rapidly expanded to become a leading British lobbying and communications agency.

There is no suggestion Wolf is breaking any rules by writing the Conservative manifesto while running a lobbying company representing major businesses, given her company makes regular declarations of its clients to the public lobbying registrar in line with current legal requirements.

However, Francis Ingham, of the Public Relations and Communications Association, which represents many leading PR and lobbying agencies, but not Public First, said: “Communications professionals have a duty to avoid conflicts of interests. There is never an excuse. The PRCA code – to which all members are bound – is explicit in this regard.”

Jon Trickett, the shadow cabinet minister with responsibility for the lobbying industry, said it was an “outrage to democracy that the frackers, the tax avoiders and the zero-hour exploiters will have the biggest say when it comes to Tory policy”. He pledged that a Labour government would strengthen lobbying regulations if it won the next general election.

Asked whether Wolf’s role as the founder of a lobbying company would impact her role with the Conservatives, a spokesperson for Public First said: “Public First has partners and staff who are members of all three major political parties and of none. Rachel is assisting the Conservative party with their manifesto based on her long experience of working on Conservative policy. Her political work is wholly separate from any commercial arrangements our firm has.”