The anonymous source, whose gender is not known, spoke of the injustice of income inequality as a driving force behind the biggest data leak in history.
In a 1,800 word document, they wrote: "Shell companies are often associated with the crime of tax evasion. But the Panama Papers show beyond a shadow of a doubt that although shell companies are not illegal, by definition they are used to carry out a wide array of serious crimes.
"Income inequality is one of the defining issues of our time.
"The prevailing media narrative thus far has focused on the scandal of what is allowed and legal in this system. What is allowed is indeed scandalous and must be changed."
They said there was a now a "new, encouraging global debate" around the issue.
While their identity is not known, they were insistent they were not a spy.
They said: "For the record, I do not work for any government or intelligence agency, directly or as a contractor, and I never have.
"My viewpoint is entirely my own."
The source also claims "several major media outlets" turned down the documents and even Wikileaks were too slow to respond to take advantage.
They wrote: "The media has failed."
The whistleblower - who used the name John Doe when contacting potential sources - also alluded to Edward Snowden.
"For his revelations about the NSA, he deserves a hero’s welcome and a substantial prize, not banishment," they wrote.
The investigation published by a global coalition of more than 100 media outlets revealed how celebrities, business leaders, criminals, sports stars and politicians from around the world use banks, law firms and offshore shell companies to hide their assets.
The list of names of those implicated in the 11.5 million records of offshore holdings covers a multitude of nationalities. Among the countries with past or present political figures named in the reports are Iceland, Ukraine, Pakistan, Saudi Arabia, Russia and Argentina, but in UK, there are some there were some that stood out above the rest.
Six peers, three Tory ex-MPs and “dozens” of UK political party donors - whose names have not yet been released - were reported to be among scores of global politicians including national leaders identified as holders of offshore assets
While there is nothing illegal in owning an offshore company, the leak of more than 11 million documents from the Panamanian law firm, Mossack Fonseca, casts an unprecedented light on the way the rich and powerful are able to use tax havens to shield their wealth. Mossack Fonseca denies any wrongdoing.
(A detailed list of all those implicated so far can be found at The International Consortium of Investigative Journalists and an explainer for offshore accounts follows this list.
The Prime Minister’s Late Father
US author and business guru, Marianna Olszewski, enlisted the help of Mossack Fonseca in order to access some of her personal fortune invested in an offshore account.
The bank that held the funds would not release the money unless they knew the identity of the person behind the company and Olszewski wished to remain anonymous.
Mossack Fonseca arranged for the company to be listed under the name of someone else - a 90-year-old British millionaire - in return for thousands of pounds a year in fees.
Andrew Mitchell QC told the BBC: “Anybody looking at all these documents will believe that it is entirely legitimately owned by this person.
“Mossack Fonseca are prepared to go to that length in order to assist their client. Basically creating a real, live human being to look to the world as if they own the assets, when in fact and in truth, they know, as their client knows, that that person is a sham.”
The Tory Baroness
Baroness Pamela Sharples is named as having links to Mossack Fonseca through Nunswell Investments Limited of which she became sole shareholder in 1995. In 2013 she is alleged to have discussed if it “made sense to defer a distribution from her Nunswell account, if she didn’t need the funds, to postpone paying taxes on it”.
The law firm currently handling her affairs said she had “no remuneration...nor any income or capital from that company”.
The Former Tory MP
Michael Mates has been linked to Mossack Fonseca though his position as chairman of Haylandale Limited which invested in property development in the Caribbean archipelago.
Mates denied any wrongdoing claiming he had not and would not receive any remuneration “unless and until the development took place, nor were the shares of any value”. He also claims the company “never really had any value”.
HM Revenue and Customs has approached the International Consortium of Investigative Journalists (ICIJ) for access to the data and said it would “act on it swiftly and appropriately”.
The World’s Best Footballer
Lionel Messi and his father, Jorge Horacio, were the ultimate beneficial owners of the Mossack Fonseca-registered Mega Star Enterprises. Although there is nothing illegal in owning an offshore company, both men are currently on trial for tax evasion.
The Film Star
Martial arts movie star Jackie Chan is reported as having having at least six offshore companies managed through Mossack Fonseca.
As yet there is no suggestion his accounts were used for the purpose of tax avoidance.
The Fifa Ethics Lawyer
Juan Pedro Damiani, a Uruguayan lawyer, is a member of Fifa’s ethics committee - the same group currently charged with reforming the organisation after recent corruption scandals.
Damiani is not accused of doing anything illegal, but a spokesman for Fifa told the BBC: “We confirm that on 19 March the investigatory chamber of the independent ethics committee was informed by the chairman of the adjudicatory chamber, Hans-Joachim Eckert, about becoming recently aware of a business relationship between the member of the adjudicatory chamber Juan Pedro Damiani, and Eugenio Figueredo Aguerre.”After receiving the information Dr Cornel Borbely, chairman of the investigatory chamber of the ethics committee, has immediately opened a preliminary investigation to review the allegations in question. Dr Borbely is currently looking into said allegations in order to determine if there is a breach against the Fifa code of ethics and decide any further measures.”
WHAT ARE OFFSHORE ACCOUNTS?
Offshore bank accounts and other financial dealings in another country can be used to evade regulatory oversight or tax obligations. Companies or individuals often use shell companies, initially incorporated without significant assets or operations, to disguise ownership or other information about the funds involved.
WHERE ARE MOST OFFSHORE ACCOUNTS?
Panama, the Cayman Islands and Bermuda are among more than a dozen small, low-tax locations that specialize in handling business services and investments of non-resident companies.
LEGITIMATE USES FOR OFFSHORE ACCOUNTS:
Companies or trusts can be set up in offshore locations for legitimate uses such as business finance, mergers and acquisitions and estate or tax planning, according to the global money laundering watchdog, the Financial Action Task Force.
ILLICIT USES OF OFFSHORE ACCOUNTS:
Shell companies and other entities can be misused by terrorists and others involved in international and financial crimes to conceal sources of funds and ownership. The ICIJ says the files from Mossack Fonseca include information on 214,488 offshore entities linked to 14,153 clients in 200 countries and territories.
EFFORTS TO CRACK DOWN ON FINANCIAL HAVENS:
The Financial Action Task Force and other regulatory agencies publish assessments identifying weaknesses in enforcement of anti-money laundering and counter-terrorism financing efforts of specific countries and territories. Financial and legal professionals get training on how to spot potential violations, since in some cases lawyers and bankers are unaware they are handling illicit transactions. The EU has stepped up efforts to crack down on tax avoidance by multinational corporations.
PAST SCANDALS OVER OFFSHORE ACCOUNTS:
Banking secrecy laws can obscure offshore financial dealings. But the disclosure of other leaked documents by the ICIJ and other organizations in late 2014 drew attention to sweet tax deals offered by the tiny European country of Luxembourg to multinational companies and ultra-wealthy individuals. In the 1980s, the Bank of Credit and Commerce International, an international bank founded by a Pakistani financier, was implicated in wide-scale money laundering and other illegal financial dealings.