NHS hospital trusts in England reported 55 cyber attacks in 2016 , according to data obtained by the BBC . The figures come from NHS Digital , which oversees cyber security , and show an increase on 16 attacks in 2015 . NHS Digital said the figures showed a `` rise in reporting , not necessarily a rise in cyber attacks '' . But Oliver Farnan , from the Oxford Cyber Security Centre , said ransomware attacks Attack.Ransom had become more common . 'The risk is going to increase ' Ransomware is software that locks computer systems and then demands a ransom Attack.Ransom to unlock the data . Oxford University Hospitals NHS Foundation Trust ( OUH ) repelled five ransomware attacks Attack.Ransom in 2016 . `` That is something a number of hospitals have seen and is potentially quite worrying , '' said Dr Chris Bunch from OUH . He added : `` Across the health service we are still to a very large extent paper-based ... and as we move increasingly towards digital records the risk is going to increase . '' Leeds Teaching Hospitals NHS Trust reported four ransomware attacks Attack.Ransom in 2016 , and University Hospitals Bristol NHS Foundation Trust and Kings College Hospital NHS Foundation Trust sustained three ransomware attacks Attack.Ransom each last year . No patient data was lost in any of the attacks on the trusts and a spokesperson for Kings College Hospitals Trust said it had a cyber security response plan that it continually reviewed and monitored . Oliver Farnan from the Oxford Cyber Security Centre , said it was hard to know if enough money was being spent on security in the NHS . `` Money is only really spent on security once everything else is up and running and in place ... it always comes second , '' he said . But David Emm , principal security researcher at internet security firm Kaspersky Lab , said basic steps such as backing up data could make a difference . `` Ransomware is a very blunt instrument , if you have a back-up of data then you are not in a position where people can extort money Attack.Ransom in that way , '' he said . However , Mr Emm said public bodies faced specific challenges , and added that money was an issue . `` They have lots of people accessing the systems , there is lots of data moving in and out of the organisation , that does actually make it harder to secure that information , '' he said . NHS Digital said it had established CareCERT which issues notices about the national threat level and publishes advice on good practice . It said its launch in October 2015 has contributed to the increase in the reporting of cyber attacks , and that more than 100 organisations had received on-site assessments to improve security .