Peter Haestrup, who founded Five Star Investment Management Ltd with Richard Cook and Prince Nawwaf bin Abdulaziz al Saud

The shadowy donor group that gave Northern Ireland’s Democratic Unionist Party (DUP) £425,000 for lavish pro-Brexit advertising during the referendum campaign has links with a Danish national who has told openDemocracy that he was involved in a notorious 1990s gun-running case in India.

On 15 February, openDemocracy revealed that the DUP had spent over a quarter of a million on Leave campaign advertisements across the UK, but that the source of this funding was secret due to the lack of donor transparency in Northern Ireland. Under pressure following our exposure of this extraordinary spend on the campaign, the DUP finally confessed that a donation of £425,000 was given to the party by a mysterious organisation calling itself ‘the Constitutional Research Council’.

Despite claims by the DUP that it has now named its donors, almost nothing is known about the Constitutional Research Council. This shadowy group has no formal or legal status and refuses to name its members, if it has any. There is no evidence that it has any way of generating income, giving it the appearance of a front organisation, set up to funnel money from secretive sources into political campaigns.

The DUP has told openDemocracy that they “don’t need to know” who the individuals behind the CRC donations are. This admission raises questions about how much the DUP checked about where the £425,000 donation was coming from, which Electoral Commission guidelines indicate they should. However, the DUP did name the CRC’s chair: former Scottish Conservative parliamentary candidate, Richard Cook.

On Friday 24 February, openDemocracy showed that Mr Cook founded a company with the former head of the Saudi Arabian intelligence service. We can now reveal that the third man named on the founding documents of this business, Peter Haestrup, is a Dane who has repeatedly been linked to a gun running case described by Indian authorities as “the biggest crime in the country's history". Mr Haestrup has never been charged with any crimes linked to the case.

In 2013 Mr Haestrup and Richard Cook set up Five Star Management, which Haestrup says was a wealth management company with a focus on the Middle East. Three-quarters of the business was owned by the now late Prince Nawwaf bin Abdul Aziz, a former head of Saudi Arabian intelligence, father to the Saudi Ambassador to the UK and a close adviser to the Saudi King. The business folded in 2014.

Haestrup, who styles himself as a ‘private banker’ and is now based outside Copenhagen, lived in England for many years. But earlier in his career he was, he admitted to openDemocracy, involved in the so-called “Purulia Arms Drop”.

In December 1995, a consignment of 548 Bulgarian AK-47 rifles, 11.3 tonnes of ammunition, 165 rocket launchers and a quantity of anti-tank weapons were parachuted from a low-flying Russian-made AN-26 plane over Purulia in West Bengal state. The arsenal was intended for a violent Hindu cult opposed to West Bengal’s provincial communist government.

The Indian Central Bureau of Investigation named Haestrup in a probe into the arms drop. Haestrup was never charged but one alleged co-conspirator, Peter Bleach, a British citizen and ex-SAS operative turned mercenary, spent eight years in a Kolkata jail, before eventually being released under pressure from the British government. The plane’s five man Latvian crew were later pardoned and released following pressure from the Russian government. Niels Holck, the reputed originator of the plot, has been the subject of repeated extradition requests from the Indian to the Danish government, but still lives in Denmark.

According to reports in a number of newspapers at the time, the Purulia conspiracy has its origins in Copenhagen in August 1995 when Holck met with British arms dealer Peter Bleach, Haestrup and another Danish national to discuss the proposed arms drop.

The “Purulia Arms Drop” was one of the most controversial episodes in modern Indian military history. Initial news reports blamed Pakistan. Then, in 1997, an Indian court named Ananda Marga, or Path of Bliss, as, the intended recipient of the wooden crates filled with guns and ammunition. The sect had a strong presence in the Purulia district and is thought to be behind one of the biggest terrorist incidents in Australian history.

Speaking to openDemocracy, Haestrup denied any wrongdoing. “If I had done anything wrong, the police would have come for me. I was working on the right side that time. When you were working in the intelligence service you have to be on the right side,” he said on the phone from his Danish home.

“Have you been a soldier? A lot of things happen in the world,” Haestrup added. “I was involved there but I (have) never been accused of anything. I have a 100% clean record.”

Haestrup says he met Richard Cook over a decade after the Purulia Arms Drop, through a banking connection in London. The pair hit it off and decided to go into business together but the “wealth management venture” never got off the ground. “We had a lot of good talks, a lot of good dinner but we never got started on the business. We did not want to do business the way the Saudis did,” Haestrup said.

In recent years, Haestrup has restyled himself as “private banker”. His GooglePlus account says he is based in Hong Kong, Monte Carlo and London. There are no photographs of Haestrup on social media, but on LinkedIn, he describes himself as CEO of the Obsideone group. While this firm no longer appears online, searches of the internet archive reveal that it was a company specialising among other things in “introductions” for “high net worth individuals”; and which promoted itself on the basis of its “discretion”. The name “Obsidione” appears to refer to “obsidion” a form of naturally occurring glass produced in volcanic rock, which is translucent rather than transparent.

Haestrup said of the Purulia Arms Drop, “‘Mr (Richard) Cook was not involved in that at all… I have never been involved in the arms trade. I have never been accused of anything and never been found guilty of anything.”

So what linked this secretive Danish businessman, a minor Conservative politician and waste management consultant who was once the Scottish representative of the Campaign Against Political Correctness, and a Saudi prince? We do not know. But what we can say for certain is that Richard Cook is – at present – the only person who has admitted to have any role in funneling £425,000 to the DUP’s Brexit campaign.

Where did this extraordinary amount of money actually come from? There has been no suggestion that Cook, who lives in a two storey house outside Glasgow, donated the money personally. So who is behind the Constitutional Research Council? And why did they donate anonymously to the DUP instead of setting up themselves as a campaigner in the Brexit referendum?

The Electoral Commission website specifically states that referendum campaigners in Northern Ireland must “make sure they know the identity of the true source” (of any funds over £500) and “check that the source is permissible”. openDemocracy asked DUP MP Jeffrey Donaldson if he could name the individuals who funded his party’s Brexit campaign. “We don't need to know who made the donations”, he said. “We have fulfilled all the requirements under electoral law. There is no further investigation under way into the DUP.”

We put Mr Donaldson’s claims to Steve Goodrich, an expert in UK political donations at the organisation Transparency International. He seemed to directly contradict the DUP MP's claims: “There are strict rules on who can donate to political parties and what needs to be reported to the Electoral Commission. Before accepting any contribution over £500, parties must check who the donor really is and whether they are actually allowed to donate. If the donor is not a ‘permissible donor’ under the rules, the party must return the money within 30 days. You can’t just accept a contribution without doing these checks.”

The most recent DUP accounts indicate that being forced to return such a large sum of money might leave the party at risk of bankruptcy.

Donaldson boasts on his website that he started his political career as assistant to one “of the greatest names in Unionism in the 20th century”, Enoch Powell, and was legally responsible for party campaign materials we photographed in Edinburgh. The Lagan Valley MP complained that openDemocracy is investigating the DUP rather than their rivals, Sinn Fein, and claimed that he could tell from our correspondent’s Irish regional accent that he wouldn’t be interested in doing so. He also said “we will be watching your website very closely to see if you are going to be fair and balanced.”

Richard Cook was contacted numerous times but did not respond to any requests for comment.