Health workers walk out today in the biggest ever NHS strike.
Tens of thousands of nurses and ambulance staff in England are taking industrial action today, with nurses due to strike again tomorrow.
Ambulance crews and call handlers will return to the picket lines on Friday.
The Royal College of Nursing and other unions have called off similar action in Wales after receiving a new pay offer from the Welsh Government.
Patricia Marquis, the Royal College of Nursing's (RCN) Director for England urged Rishi Sunak to come to the table and negotiate, telling Times Radio: "We have asked and called urgently on Rishi Sunak to come to the table to seek a resolution"
She went on: "We don't want to impact on patients. We don't want to disrupt services.
"But the reality is, ... every day 1000s of patients operations are being cancelled, because there aren't enough staff to to deliver either the operations or the outpatient services that are needed.
"And so we don't want to continue to disrupt. We have asked and called urgently on Rishi Sunak to come to the table to seek a resolution"
She also said the union would call off strikes if there are "genuine negotiations".
Scroll down for a map and full list of strike locations.
In a letter to the Prime Minister, RCN general secretary Pat Cullen said that a "meaningful" pay offer from the Government could still avert strike action.
She drew a comparison with his swift action sacking Conservative Party chairman Nadhim Zahawi after he was found to breached the ministerial code in relation to his tax affairs.
"As shown by last weekend's fast-paced changes in Cabinet, big decisions can be made by you at any point in the week in the interests of good government," she wrote.
"I am urging you to use this weekend to reset your government in the eyes of the public and demonstrate it is on the side of the hardworking, decent taxpayer.
"There could be no simpler way to demonstrate this commitment than bringing the nurse strike to a swift close."
STRIKE MAP WIDGET: Enter your postcode below and hit the READ MORE button to see the nearest hospital to you where nurses are going on strike
Here's a full list of trusts affected by the strikes.
ENGLAND
North West
Lancashire Teaching Hospitals NHS Foundation Trust
Wrightington Wigan and Leigh NHS Foundation Trust
Countess of Chester Hospital NHS Foundation Trust
Liverpool University Hospitals NHS Foundation Trust
Mid Cheshire Hospitals NHS Foundation Trust
Wirral University Teaching Hospital NHS Found Trust
St Helens and Knowsley Teaching Hospitals NHS Trust
Tameside and Glossop Integrated Care NHS Foundation Trust
North West Ambulance Service NHS Trust
Liverpool Heart and Chest Hospital NHS Found Trust
The Clatterbridge Cancer Centre NHS Found Trust
The Christie NHS Foundation Trust
Liverpool Women’s NHS Foundation Trust
Alder Hey Children’s NHS Foundation Trust
The Walton Centre NHS Foundation Trust
Northern
University Hospitals of Morecambe Bay NHS Foundation Trust
The Newcastle Upon Tyne Hospitals NHS Foundation Trust
South Tees Hospitals NHS Foundation Trust
Northumbria Healthcare NHS Foundation Trust
County Durham and Darlington NHS Foundation Trust
Gateshead Health NHS Foundation Trust
North East Ambulance Service NHS Trust
Yorkshire & The Humber
Barnsley Hospital NHS Foundation Trust
Bradford Teaching Hospitals NHS Foundation Trust
York and Scarborough Teaching Hospitals NHS Foundation Trust
Harrogate and District NHS Foundation Trust
The Leeds Teaching Hospitals NHS Trust
Sheffield Teaching Hospitals NHS Foundation Trust
Sheffield Children’s NHS Foundation Trust
West Midlands
Worcestershire Acute Hospitals NHS Trust
University Hospitals Birmingham NHS Foundation Trust
The Royal Orthopaedic Hospital NHS Foundation Trust
Birmingham Women's and Children's NHS Foundation Trust
Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust
East Midlands
Nottingham University Hospitals NHS Trust
Kettering General Hospital NHS Foundation Trust
East Midlands Ambulance Service NHS Trust
London
Imperial College Healthcare NHS Trust
Guys and St Thomas NHS Foundation Trust
Great Ormond Street Hospital for Children NHS Foundation Trust
St George's University Hospitals NHS Foundation Trust
Kings College Hospital NHS Foundation Trust
University College London Hospitals NHS Foundation Trust
Royal Marsden NHS Foundation Trust
South East
University Hospitals Sussex NHS Foundation Trust
Queen Victoria Hospital NHS Foundation Trust
Oxford University Hospitals NHS Foundation Trust
Portsmouth Hospitals NHS Trust
University Hospital Southampton NHS Foundation Trust
Royal Berkshire NHS Foundation Trust
Oxford Health NHS Foundation Trust
East Sussex Healthcare NHS Trust
South East Coast Ambulance Service
South Central Ambulance Service NHS Foundation Trust
South West
Gloucestershire Hospitals NHS Foundation Trust
University Hospitals Plymouth NHS Trust
University Hospitals Bristol and Weston NHS Foundation Trust
Dorset County Hospital NHS Foundation Trust
Royal Devon University Healthcare NHS Foundation Trust
Great Western Hospitals NHS Foundation Trust
Salisbury NHS Foundation Trust
University Hospitals Dorset NHS Foundation Trust
Royal Cornwall Hospitals NHS Trust
Royal United Hospitals Bath NHS Foundation Trust
North Bristol NHS Trust
Torbay and South Devon NHS Foundation Trust
Somerset NHS Foundation Trust
South Western Ambulance Service NHS Found Trust
Eastern
Norfolk and Norwich University Hospitals NHS Foundation Trust
Cambridge University Hospital NHS Foundation Trust
West Suffolk NHS Foundation Trust
East Suffolk and North Essex NHS Foundation Trust
Royal Papworth Hospital NHS Foundation Trust