A "shockingly low" number of fraud reports are being successfully cleared up, a consumer group claims.

Which? said its analysis of available figures found more than 96 per cent of crimes reported to UK body Action Fraud are closed without a successful outcome.

The group said its findings suggest a "losing battle" is being fought against this crime.

Those representing police and the finance industry said a strong focus is put on preventing fraud happening in the first place as well as solving cases.

Some crimes reported to Action Fraud, which acts as a central point of contact for victims of scams, may end up being passed on to a local police force for investigation, typically one where the suspect lives.

Which? also submitted freedom of information (FOI) requests to 43 police forces across the UK, asking them to provide data on fraud investigations.

Of those that responded, 29 out of 30 had seen their performance slip between 2014 and 2016, the consumer group said.

Which? also said it had found a "lack of transparency" around the available statistics for fraud.

It claimed the current process for investigating fraud can be slow, which could in part be due to the need to request data from banks.

Ceri Stanaway, Which? money editor, said: "The shockingly low success rate for fraud investigations is leaving many victims deprived of justice and suggests the authorities are fighting a losing battle against this type of crime.

"Unfortunately, investigations are often conducted at a slow pace - with communication between banks and the authorities often dragging on for weeks before police can launch a full inquiry.

"We'd urge consumers to be extremely cautious when dealing with unsolicited contact as fraud is on the rise."

Action Fraud is run by the City of London Police and works alongside the National Fraud Intelligence Bureau.

A statement from City of London Police said: "Fraud is the fastest-growing crime in the UK and this means that it is not always possible to enforce our way out of the problem; due to the high volume of cases it is not possible for every report of fraud to result in a judicial outcome.

"For this reason, it is important that law enforcement not only focuses on pursuing suspects, but also works to prevent and protect people from fraud.

"The City of London Police's National Fraud Intelligence Bureau disrupts email addresses, bank accounts and phone lines associated in fraudulent activity. In 2016-17, 170,856 disruption requests were made."