Switzerland’s second largest bank, Credit Suisse, is at the centre of an international tax evasion case involving 55,000 suspect accounts and the seizure of millions of euros in cash, gold, jewellery, real estate and paintings.

In a fresh blow to Switzerland’s attempts to clean up its reputation for banking secrecy and tax evasion, the Netherlands is leading a coalition of five tax authorities conducting a criminal investigation into undeclared “black” accounts and money laundering.

Raids on homes and offices took place across the Netherlands and France on Thursday and Friday. Taxpayers and high ranking bank employees in Britain, Germany and Australia are under investigation.

Dutch prosecutors acted after receiving a tip-off on assets hidden within “offshore accounts and policies”, estimated in the millions of euros. They say the information concerns a single Swiss bank, but have so far declined to name the target.

However, Credit Suisse confirmed on Friday that its offices in London, Paris and Amsterdam had been searched by local authorities concerning “client tax matters”, and that it was cooperating with their inquiries.

The action has prompted fresh calls for an end to Swiss banking secrecy. If proven, evasion on this scale would amount to a “global criminal enterprise”, one tax expert said.

The UK’s HM Revenue & Customs said it has launched a criminal investigation into suspected tax evasion and money laundering by a global financial institution and its employees. Warning of “further, targeted, activity over the coming weeks”, HMRC said its efforts were focused on the bank’s staff and “a number of its customers”.

The raids sparked a diplomatic row between Switzerland and the Netherlands, with officials in Geneva furious at what they claim was a deliberate decision to keep them in the dark.

“The Swiss public ministry is stupefied by the manner in which this operation has been organised so as to keep Switzerland deliberately excluded,” a government spokesperson said. “The public ministry awaits a written explanation from the Dutch authorities.”

Two arrests have been made in the Netherlands, where the haul of assets seized from safes and homes in the Hague and other areas included property, cash, 35 paintings worth €1.2m (£1m), a luxury Mercedes, and a 1 kilogram gold ingot.

A Mercedes car confiscated in the raid by the FOID. Photograph: FIOD

The country’s Fiscal Information and Investigation Services (FIOD) has reportedly been handed the names of 3,800 account holders and details of 55,000 accounts by a Dutch informant. Dozens of Dutch taxpayers are under investigation. More actions would follow in the coming weeks, the agency said in a statement released on Friday.

France announced that 25 customs agents had carried out raids across the country as part of an inquiry into “aggravated money laundering and financial fraud” which began on 26 April last year. Investigators have found “several thousand” bank accounts opened in Switzerland by French taxpayers who are suspected of having failed to declare them to the authorities.

“The international dimension of these kind of frauds, which are particularly damaging to the public finances, justifies an efficient coordination between european and international countries,” the financial prosecutor’s office said in a statement.

Numbered Swiss accounts, notorious for their use in concealing funds, were used by Australians caught up in the investigation, a federal minister said on Friday. More than 340 individuals have been identified. They were described in a statement by Australia’s minister for revenue and financial services Kelly O’Dwyer as having links to Swiss banking relationship managers alleged to have “actively promoted and facilitated tax evasion schemes”.

“The fact that these accounts are unnamed means that by their very nature they are likely to have been established to hide the identity of the owner,” O’Dwyer said. In the coming week, Australia’s Serious Financial Crime Task Force will interview bank staff, taxpayers and lawyers.

Gold coins also confiscated in the FOID raid. Photograph: FIOD

The action is being coordinated by a European Union agency in the Hague which fosters judicial co-operation. In a statement the agency, Eurojust, said: “The independent investigations gathered evidence and analysed a huge amount of data. The undeclared assets hidden within offshore accounts and policies are estimated in the millions of euros.”

Eurojust held three coordination meetings to share information and devise a strategy for last week’s action. “International cooperation will be intensified, and the roles that possible service providers have played will be examined,” the agency stated.

“Any notion that Swiss banks are better at banking than other banks in other countries is simply untrue, they just don’t play by the rules,” said the tax lawyer Miles Dean, of Milestone International Tax.

Alex Cobham, chief executive of Tax Justice Network, said: “Allegations of laundering and tax evasion on this scale would, if proven, indicate the bank was effectively a global criminal enterprise.”

The MP Margaret Hodge said the case demonstrated the need for reform in tax havens. She urged support for an amendment to the criminal finances bill which would force British jurisdictions like Jersey and Guernsey to publicly name the owners of offshore companies by 2020. The House of Lords is due to vote on Hodge’s transparency clause next week.

“We hope that the evidence that secrecy in places like Switzerland feeds evasion and avoidance is heard by their lordships when they come to vote on this,” she said. “There is a massive industry of people making a lot of money working for accountants, lawyers advisers and banks, far too many of whom are complicit in aggressive avoidance and evasion.”

A spokeswoman for Credit Suisse confirmed its offices had been visited by authorities. In a statement the bank said: “On 30 March 2017, Credit Suisse offices in London, Paris and Amsterdam were contacted by local authorities concerning client tax matters. We are cooperating with the authorities.”







