Patients are 15% more likely to die if they are admitted to hospital on a Sunday than a Wednesday, Health Secretary Jeremy Hunt has said.
Giving a speech at the King's Fund, he claimed this leads to 800 "avoidable deaths" a month.
"I've yet to meet a consultant who would be happy for their relative to be admitted on a weekend," he said.
Other mistakes which should never happen include operations carried out on the wrong side of the body - which occurs on average twice a week.
Hunt said: "Hospitals up and down the country are making the same tragic mistakes. We need a more human-centred system which puts patients rather than targets first."
Launching 'NHS Improvement', which he wants to be the "safest healthcare system in the world", he said in the next five years he expected:
- The majority of doctors to be on a seven-day working week which means they would work weekends but not more hours than is safe.
- A new 'no-blame' patient safety service to be set up to reduce fatalities and costs.
- Seamless access to electronic health records which can be shared
- NHS trusts to be enrolled in a "buddying programme" with Virginia Mason Hospital in Seattle, which is billed as the safest hospital in the world.
- The introduction of new medical devices which can send emergency alerts to ensure ambulances arrive quicker.
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