Renewed calls have been made for a wholesale review of Scotland's increasingly notorious anonymous shell firms after it emerged they were used to break sanctions against Vladimir Putin's Russia.

Politicians and anti-corruption campaigners have already secured UK government moves to try to make widely abused Scottish limited partnerships or SLPs name their main owner, if they have one.

However, the SNP and Transparency International have stepped up demands for deeper reforms of the firms, which they describe as "Britain's home-grown secrecy vehicle".

FULL INVESTIGATION: How a Scots council house was secret base for criminals busting Putin sanctions

Their calls came after the Sunday Herald revealed that two now dissolved throw-away SLPs were used as owners and operators of two ships used to break an international embargo of trade with the Russian-occupied Ukrainian territory of Crimea.

The true owners of the SLPs, Importica of Inverness and Edison Project of Edinburgh, would face jail time of up to eight years and seizure of their property if they were exposed. Scotland's secrecy regime, however, protects them.

One of the firms, Importica, owned a ship called the Tallas which is currently floundering off Istanbul after being abandoned their after a sanctions-busting trip to Crimea. Its crew was left on the ship living off fish from the sea and rain water for at least eight months.

The Tallas, listing off Istanbul 

HeraldScotland:

Glasgow Central MP Alison Thewliss wants the UK Government, which is responsible for Scots corporate law, to act quickly to try to stop SLPs being used as secret ship owners.

She said: "To find ourselves in a circumstance where a blockade-running ship theoretically has an anonymous owner yet has been operated via a house in Inverness demonstrates precisely why the campaign around Scottish Limited Partnerships is absolutely imperative.

"The opaque structures of shell companies and SLPs have provided an ideal platform for criminality to flourish.

"In this instance the flag flown by the ship was Cambodian, the ship is sinking off Istanbul, the actual address of the owner is in Crimea, and yet the address provided for the owner is a home in Inverness.

"The so-called flags of convenience hold links to some of the most harrowing experiences of international criminality, from providing a platform for human trafficking to enabling the violation of sanctions. "To begin to tackle this, we must expose and eradicate blockade-running ships.

"To do so involves significantly enhancing transparency around the shell companies that so many of them are being operated by."

There is some evidence that registrations of new SLPs fell back after new rules were imposed last month forcing any person of significant control to be named.

Transparency International, however, believes early signs are that compliance with the new rules are slow amid question marks over whether such modest reforms other own will work.

Steve Goodrich, of the campaign group, writing in today's Herald, warned that British eagerness to register firms for foreigners was potentially dangerous.

He said: "As we head closer towards Brexit, politicians from all parties are keen to show the UK is still open for business. However, this openness is being exploited on an industrial scale by those seeking to steal from some of the most impoverished and downtrodden people in Europe. If the UK is to avoid getting a reputation as the clearing house for the corrupt, the government needs to end its role as an offshore on the edge of the continent."

International observers warn of the dangers of ships using offshore firms for owners, such as Scottish ones, and flags of convenience like Cambodia's.

Andrii Klymenko is an expert who monitors sanctions-busting in Crimea for a Kiev-based think tank called the Maidan of Foreign Affairs. He stressed that Importica's Tallas and the ship owned by Edison Project, the Vitaliy Satik, had committed serious crimes.

He said: "These two ships have not just breached international sanctions, they have broken the law of Ukraine.

"According to the Criminal Code of Ukraine, Arcticle 332-1, the penalty for breaking the rules for entering occupied territory is up to eight years in prison and the seizure of any ship or vehicle.

"This article does not only apply to the crew and the organisers of the journey. It also applies to the ships' owners and operating companies.

"In other words, even if there were no sanctions, these people would be criminals who had breached our state border."

Ukraine's prosecutors, police and SBU secret service are working with international partners to trace foreign fronts and vessels outside Ukraine.

Mr Klymenko added: "I am sure that in the near future we shall see formal investigations in those countries of sanction-busting in those countries which support the sanctions.' That includes the UK.