The Serious Fraud Office (SFO) has dropped an investigation into troubled banknote maker De La Rue over allegations of fraud at its South Sudan business division.

In a short statement, investigators said: “Following extensive investigation and a thorough and detailed review of the available evidence, the SFO has concluded that this case did not meet the relevant test for prosecution as defined in the Code for Crown Prosecutors.”

The investigation had first been launched in July last year and was looking at allegations of serious fraud, bribery and corruption from De La Rue and associates in a country it has worked for since the nation’s inception in 2011.

De La Rue, which prints notes for the Bank of England, issued a statement saying: “De La Rue is pleased that the SFO has closed its investigation and that the SFO is taking no further action in respect of this matter.”

The company, which also makes passports and other secure documents, has struggled in recent years as shoppers and businesses switch to contactless payments.

The move to a cashless society has increased due to the coronavirus lockdown, but bosses have remained confident that contracts in place would keep its currency factories working at high capacity for the rest of the year.

Apart from one site in Sri Lanka, which stopped production for eight weeks, all the company’s factories have remained open throughout the pandemic.

Nor has it seen “material problems” in getting materials from suppliers.

De La Rue also revealed a new five-year contract with the Australian government to print pages for the country’s new passport.