THE Royal Berkshire Hospital has been targeted in a major hacking attack that has affected numerous NHS hospitals.

The trust's radiotherapy department has been hit by a ransomware attack locking staff out of key systems.

Trusts across the country have been attacked by the scammers at 3.30pm this afternoon.

A Royal Berkshire Hospital spokesman said: "It seems we have been affected but we are unsure of the scale yet.

"We have some patient clinics over the weekend but the doctors have a tried and tested backup with paper.

"It doesn't at the moment affect clinics for the weekend although there may be some delays as we go to the paper system.

"We have a potential issue with some of the phones connected to the NHS England system."

Some 16 organisations have had files locked by the 'Wanna Decryptor' malware, demanding a $300 ransom for them to be returned.

Ambulances have been diverted and patients warned to avoid some A&E departments as doctors have had to resort to using paper and pens to keep .

An NHS Digital spokesman said: "At this stage we do not have any evidence that patient data has been accessed.

"We will continue to work with affected organisations to confirm this.

He added the attack 'was not specifically targeted at the NHS and is affecting organisations from across a range of sectors'.

Hospitals and clinical commissioning groups in London, Blackpool, Hertfordshire and Derbyshire have also reported being hit in the attack.

The Patients' Association condemned the criminals behind the cyber attack on the NHS but said lessons from earlier incidents had not been learned.

In a statement the group said: "We should be clear that responsibility for today's apparently extensive attack on NHS IT systems, and for any harm that occurs to patients as a result, lies with the criminals who have perpetrated it.

"From reports so far, the attack appears to have been highly coordinated and aggressive and a police investigation will no doubt be required.

"However, that something of this sort could happen will surprise few people.

"It has long been known that the NHS struggles with IT in multiple respects and that this includes serious security problems.

"Though today's may be the largest attack of this sort, it is not the first - yet the lessons from earlier incidents have not been learnt.

"The power of IT in transforming services for patients is undoubted, yet the NHS has struggled to harness it: centralised approaches have failed badly, while smaller scale local projects can easily give rise to huge variations in both quality and security.

"We are seeing today that IT security is critical to patient safety."

The malware

Wanna Decryptor is a piece of malicious software that encrypts files on a user's computer, blocking them from view and threatening to delete them unless a payment is made.

The virus is usually covertly installed on to computers by being hidden within innocent-looking emails containing links, which users are tricked into opening.

Once opened, the malware can install on to a system without the user's knowledge.

The virus is then able to encrypt files and block user access to them, displaying a pop-up window on-screen telling users they have been blocked and demanding payment - often via a digital currency such as Bitcoin.

Transactions through digital currencies such as Bitcoin are harder to trace as they do not involve a central banking system to process or confirm transactions, instead relying on other users to do so in a peer-to-peer system, which increases the chances of anonymity.

It is possible to remove ransomware such as Wanna Decryptor without payment by using advanced anti-malware software.

The malware can also be removed manually with a computer in "safe mode", however security experts warn this runs the risk of damage to a PC as users must go through sensitive system files in order to find and isolate files created by the Wanna Decryptor software.