NHS services across England and Scotland have been hit by a large-scale cyber-attack. Here is a list of all of the services that we know to have been affected.
The Royal Berkshire Hospital confirmed the IT system used for discharges had been affected, so staff reverted to paper. However, the patient records system was not affected. The hospital said patient safety is not being compromised, but warned people to expect some delays.
It is understood that the NHS Cumbria Clinical Commissioning Group (CCG) was told to switch off all its IT systems. It is not clear whether GP surgeries were affected.
North Cumbria University Hospital Trust, which includes Cumberland Infirmary in Carlisle, the West Cumberland Hospital in Whitehaven, and the maternity service at Penrith Community Hospital, confirmed on Twitter that its hospitals had been affected. However, it said that the hospital was "working as normal".
The Cumbria Partnership Foundation NHS Trust, which runs 60 community and mental health services across the county, also confirmed on Twitter it had been affected, but again said their services were working as normal.
Derbyshire Healthcare NHS Trust said it had not been affected by the attack, but had switched off its IT systems.
North Derbyshire CCG said it was taking action, but GP surgeries in the area told the BBC they had not been affected.
Southern Derbyshire CCG also told all of its GP surgeries to switch off their IT systems.
Colchester Hospital University NHS Foundation Trust, which includes Colchester General Hospital and Essex County Hospital, confirmed it was affected by the attack to BBC Essex.
Mid Essex Hospital Services NHS Trust released a statement saying that their hospitals - Broomfield Hospital, St Michael's Hospital, St Peter's Hospital and Braintree Community Hospital - had been affected. It asked people not to attend A&E unless they had a life threatening condition or emergency.
Hampshire Hospitals NHS Foundation Trust, which includes Andover War Memorial Hospital, Basingstoke and North Hampshire Hospital, and the Royal Hampshire County Hospital, was affected by the attack. A statement from the Trust said it had affected "some services" and asked for people to consider whether they needed to go to the emergency departments, suggesting calling 111 for healthcare advice.
East and North Hertfordshire NHS Trust, which includes Lister Hospital, Hertford County Hospital, Mount Vernon Cancer Centre and the New QEII Hospital, confirmed it was having problems with its IT systems and telephone network.
West Hertfordshire Hospitals NHS Trust, which includes Watford General Hospital, Hemel Hempstead Hospital and St Albans City Hospital, was affected.
Hull and East Yorkshire NHS Hospitals Trust, including the Hull Royal Infirmary and Catle Hill Hospital, confirmed it had been affected. A spokesperson for the Trust said, whilst they had detected the malware, it had "not had a significant impact on our organisation". All incoming email and all web mail was blocked, but no patient systems had been affected.
NHS Heywood, Middleton And Rochdale CCG said they had put continuity plans into place, with GPs using paper back-up.
Other organisations confirmed as being affected were the Trafford Hospitals Trust, Wigan Hospitals Trust, Manchester Royal Infirmary (part of the Central Manchester University Hospitals NHS Foundation Trust), Bolton CCG and Bury CCG.
East Lancashire NHS Trust confirmed via its Twitter account that all of their hospitals had been affected and their IT teams were working to fix the issues.
Morecambe Bay NHS Trust also confirmed IT problems on Twitter and asked people not to attend A&E unless it was an emergency.
A Blackpool CCG spokesman confirmed to the BBC that the attack had shut down the majority of their systems, affecting GPs, hospitals and walk-in centres. He said they believed it got onto their computers via the Lancashire NHS network and had affected their patient records system, called EMIS.
Waterloo Medical Centre in Blackpool told the BBC it had been affected by the attack.
Lancashire Teaching Hospital NHS Trust confirmed they were affected, including Royal Preston Hospital and Chorley Hospital.
Barts Health NHS Trust, which includes Barts Hospital, the Royal London Hospital and Whipps Cross University Hospital, was affected by the attack.
United Lincolnshire Hospitals Trust, which includes Grantham Hospital, Lincoln County Hospital and Pilgrim Hospital, was affected. The Trust's chief operating officer, Mark Brassington, said all IT systems and many phone lines had been switched off, and they were diverting some emergency cases to other local hospitals.
Northern Lincolnshire and Goole NHS Foundation Trust confirmed they had been affected by the attack and advised people to only go to A&E if it was urgent.
A GPs' practice with surgeries in south Lincolnshire and across the border in Cambridgeshire was also hit, with many patients having to be sent home.
Liverpool Community Trust has confirmed some IT systems were affected and GP surgeries in the city had gone back to using paper.
Southport and Ormskirk Hospital NHS Trust was also hit and asked people with outpatient appointments on Saturday not to attend, promising to call on Monday to rearrange. It asked people to avoid A&E if possible.
James Paget University Hospitals Foundation Trust was hit by the attack.
Northumbria Healthcare NHS Foundation Trust, which includes Alnwick Infirmary, Berwick Infirmary, Blyth Community Hospital, Haltwhistle War Memorial Hospital, Hexham General Hospital, Morpeth NHS Centre, North Tyneside General Hospital, Northumbria Specialist Emergency Care Hospital, Rothbury Community Hospital, the Whalton Unit and Wansbeck General Hospital, was affected, with people asked to avoid A&E where possible.
NHS Dumfries and Galloway, including Dumfries and Galloway Royal Infirmary and Galloway Community Hospital, was affected.
NHS Greater Glasgow and Clyde said four GP practices had experienced disruption to IT systems, but the rest of the area was unaffected.
NHS Forth Valley confirmed that a small number of GP and dental practices had been affected, but remained open.
NHS Lanarkshire closed down its non-essential networked IT systems on a temporary basis after being affected by the attack. All their sites remained open, but they have asked members of the public only to attend hospital for emergency treatment.
An NHS Western Isles spokeswoman confirmed they had been affected but could not confirm to what extent.
University Hospitals of North Midlands said they were taking precautionary measures only. A spokesman for the Trust, which runs Royal Stoke and County Hospital in Stafford, said: "Certain services within UHMN are currently unavailable. This is having minimal impact on clinical services. Staff and partners will be kept fully informed throughout the disruption." People have also been asked to stay away from A&E if possible.