Corporate lobbyists who peddle the interests of big business remain shrouded from public scrutiny as lax lobbying regulation increases the risk of corruption in Britain, a scathing new report warns.

Following detailed analysis of figures from England, Scotland, Wales and Northern Ireland, Transparency International UK (TI UK) found the UK’s lobbying register is “entirely unfit for purpose.”

The think tank, which seeks to fight corruption in all its forms, says the British public is “left in the dark” as unaccountable architects of public-policy mold Britain’s political landscape.

Less than 4% of lobbyists are covered by UK lobbying register and it's unfit for purpose according to @TransparencyUKhttp://t.co/0nYTE0gmx8 — TI EU Office (@TI_EU) September 22, 2015

A new report by TI UK, titled “Accountable Influence,” indicates less than four percent of Britain’s lobbying sphere is regulated despite the fact it is dominated by corporate interests.

The research, which was published on Tuesday, marks the launch of the think tank’s campaign to highlight the importance of transparency in the battle against corruption.

Lobbyists affect the spending of billions of pounds of public money in Britain, yet are largely unaccountable. TI UK argues increased transparency would help ensure the government works in the public interest, rather than the interest of big business.

The think tank’s report shows 80 percent of Britain’s most frequent lobbyists stem from the corporate world and represent the interests of FTSE 100 companies.

It also uncovered potential conflicts of interest, following scrutiny of MPs advisory roles. The report revealed a total of £3.4 million was paid to 73 MPs in 2014 for work they conducted outside of their day jobs. While payments for parliamentary advice is still legal in the House of Commons, TI UK notes it is outlawed in the House of Lords, in Scotland and in Wales.

In a report published in 2013, Britain’s Committee on Standards in Public Life said all those who serve in public office should display selflessness, integrity, objectivity, accountability, openness, honesty and leadership in their work.

However, TI UK says money continues to influence policy in the UK as vested interests infiltrate political decision making. While some lobbying is legitimate and makes a valuable contribution to policy, lapses in ethics and lobbying abuses surface frequently in Britain.

Only 50% of MEPs agree that the EU lobby register reduces undue influence in lobbying, according to UCL survey @Timmermans@sylvieguillaume — TI EU Office (@TI_EU) September 22, 2015

Although lobbying scandals damage public trust in public institutions, many lobbying abuses are legal, TI UK warns.

In a report published in February 2015, the anti-corruption think tank highlighted 39 separate examples of lobbying loopholes that exist in Britain. In each of these cases, lax UK legislation offers a green light for behavior that can foster corruption.

TI UK calls for more comprehensive data to be published on meetings held by lobbyists in Britain.

Speaking on Tuesday, the group’s head of research and advocacy Nick Maxwell called upon the government to introduce a statutory register of lobbyists.

Maxwell said this register should include “both in-house and consultant lobbyists,” and provide the public with more “accurate, accessible, intelligible and meaningful information” on the meetings they hold. He also called on the government to introduce a fully independent watchdog responsible for monitoring Britain’s lobbying sphere.