The creators of a messaging app accused of handing user data to the Iranian regime live on a windswept hill in a British coastal town, the Guardian can reveal.

Hadi and Mahdi Anjidani are the cofounders of TS Information Technology, established in 2010 and now registered at the address of a tax accountancy in Shoreham-by-Sea in West Sussex. It is the UK branch of an Iranian software corporation, Towse’e Saman Information Technology (TSIT).

The company makes popular computer games, a payment platform capable of helping Iranians skirt sanctions, and Gap Messenger, a sleek purple messaging app billed as an Iranian alternative to Telegram.

But while Gap’s public profile says the app is encrypted and does not share its data with third parties, Iranian digital rights experts say their investigations contradict those claims.

A report from FilterWatch, an organisation monitoring Iran’s internet censorship, has accused Gap Messenger of being among the “main actors and entities that participate in the Iranian government’s internet control and suppression efforts”.

Mahdi Anjidani, TSIT’s chief executive, has also widely espoused pro-regime views in Iranian media – including pushing for draconian censorship measures on a broadcast by state television.

A report from an Iranian independent newspaper suggests that one of his businesses, a social network called Virasty, has a government partner in the form of the former Iranian deputy communications minister Amir Mohammadzadeh Lajevardi. Anjidani has also posted a picture to Facebook appearing to show himself and the former Iranian president Mahmoud Ahmadinejad.

Gap and Anjidani’s other platforms are a part of Iran’s domestic internet, a parallel network inside the country. Developed over the course of a decade, this national internet offers a skeletal, government-controlled option for connectivity to 93 million people who are otherwise almost completely cut off from the outside world.

The national internet is a tool designed to enable the longer-term survival of a regime that has killed possibly tens of thousands of people in the past weeks as part of a crackdown on escalating anti-government protests.

That crackdown has been accompanied by one of the most severe internet shutdowns in history, a precise, fine-tuned blackout intended, say experts, to cut off Iranians while allowing their government to continue to function and make money.

A feature of the national internet is domestic messaging apps, which Iranian authorities have energetically promoted over the past years, and which include Gap. Several separate Iranian digital rights experts said the point of these apps was to shepherd users on to platforms the regime could monitor.

“The overall point is control. Local platforms make it easier to monitor conversations, collect data, and silence dissidents, without the legal and technical barriers that exist for global services,” said a researcher at Outline Foundation, an anti-censorship organisation. “This isn’t about boosting local innovation. It’s about consolidating surveillance and shrinking the space for independent expression.”

Gap boasts more than 1m downloads on Google’s Play store, and 4m more on Cafe Bazaar, an Iranian app store. It offers a built-in payment service, as well as games, online calls and animal-themed stickers.

FilterWatch’s report concluded that Gap Messenger appeared to have at least once handed over information on its users to Iranian censorship authorities, according to emails leaked from the attorney general’s office in late 2022.

Neither Mahdi nor Hadi Anjidani responded to emails from the Guardian. When a reporter knocked on the door of the Brighton home address where TS Information Technology was first registered, Hadi briefly opened the door, then shut it without a word. A neighbour said the family was reclusive, and rarely interacted with the rest of the neighbourhood.

At the BizSpace workspace in nearby Hove, where TS Information Technology keeps an office, a receptionist said Hadi Anjidani had used the space for at least 13 years, but came in only for appointments. A phone call to this office went unanswered.

In Iran, Mahdi Anjidani has been featured on a podcast and profiled as an up-and-coming tech entrepreneur. His Facebook account highlights high-profile meetings: with the son of Dubai’s Sheikh Makhtoum, as well as with Ahmadinejad, who in one picture appears to be standing next to a table displaying Anjidani’s game Kings Era.

In an interview with an Iranian tech publication, Mahdi Anjidani described himself as a “child of the Islamic Revolution” and praised Iran’s elites for overcoming international sanctions by “turning threat into an opportunity” and meeting the country’s software needs.

In another interview, with an Iranian startup accelerator, Anjidani appeared to field questions about getting around sanctions on Iran, government support for his app, and his “satellite offices” in England, Turkey and the United Arab Emirates.

On a 2024 broadcast by Iranian state media, he inveighed against foreign-owned messaging apps and VPNs – tools that allow Iranians to circumvent surveillance – and appeared to suggest ways the government could crack down on these.

Anjidani was “reiterating the threats of the government, which shows how close he is to the government”, said an Iranian researcher who asked not to be named, fearing reprisals.

While the ongoing internet shutdown means Iranian corporate records are largely unavailable, Gap Messenger is not the whole extent of Hadi and Mahdi Anjidani’s business. Archived versions of their site and public information connect them to an array of companies, including an Iranian social network, an SMS-based advertising service, and MihanPayment, a platform that integrates with the Iranian banking system to allow Iranians to perform international transactions.

Another Iranian digital rights researcher said the privileges of creating and operating domestic platforms such as these in Iran were reserved for a few: “Anyone who is allowed to have a messaging app in the country – you’re talking about the level of oligarchs around Putin.”