Financial pressures on the NHS could be fuelling growing costs for clinical negligence in a "vicious spiral" that could "spin out of control" without urgent action, MPs have warned.
The Public Accounts Committee (PAC) found the annual cost of clinical negligence for NHS trusts had quadrupled over the last decade, from £400 million in 2006/07 to £1.6 billion in 2016/17, taking already scarce resources away from patients and frontline services.
Budget pressures on the NHS have already affected waiting times and quality of care, risking even more clinical negligence payouts as almost 40% of claims relate to a failure or delay in diagnosing or treating a patient, they said.
The financial strain is also putting "huge pressure" on NHS staff which may affect their ability to deal effectively with complaints, and spending on clinical negligence is forecast to increase from 1.8% of trusts' income in 2015/16 to 4% by 2020/21.
Meg Hillier, who chairs the influential committee, said: "I am concerned that funding available for NHS services and the costs of clinical negligence are locked in a vicious spiral - one that without urgent action will spin out of control.
"In just a decade we have seen a four-fold increase in the annual cost to trusts of such negligence, depriving frontline care of badly needed funds and therefore heightening the risk of further increases in negligence claims.
"Of course it is important that patients who suffer because of clinical negligence are compensated. But Government has been far too slow to understand and get a grip on the increase in negligence costs."
She added: "The NHS is operating under considerable financial pressure and, as the Public Accounts Committee has warned repeatedly, there are already serious threats to its financial sustainability.
"It is unacceptable for patients to suffer the effects of further cost pressures caused by Government's sluggish response to the issues raised in our report."
The committee also warned that the NHS had a "predominantly defensive" culture when things went wrong, limiting its ability to learn lessons.
The MPs said there was a growing body of evidence which showed many people simply wanted an apology when things went wrong, or an acknowledgement that the issue was being dealt with and would not be repeated.
But if they were dissatisfied with the response they received from trusts following a harmful incident, they may make a negligence claim, the report said.
It also pointed to recent research which suggested greater transparency did not lead to more claims.
Ms Hillier said: "The NHS must move more quickly to share best practice in the handling of harmful incidents and complaints.
"This should be a fundamental part of what remains a disappointingly slow-moving shift towards openness and transparency.
"Whistleblowers in the NHS are too often seen as a problem. What's needed is a more open culture so that mistakes are acknowledged and learnt from."
A Government spokeswoman said: "Clinical negligence costs are too high, so we are working on proposals to fix the amount that legal firms can recover from clinical negligence cases and provide families affected by severe avoidable birth injuries - a leading cause of clinical negligence costs - with an alternative to lengthy court disputes.
"But there is still more to do, that's why we will look at all the options to develop a coherent strategy to tackle the rising costs, which will be supported by our relentless pursuit of improved safety standards and a transparent learning culture across the NHS."