Clinical negligence claims went up almost 18% over the last year despite changes to the law banning no-win no-fee agreements, an NHS review has found.
The spike was due to new solicitors entering the market to chase lucrative no-win no-fee claims before new rules came into effect in April 2013, the NHS Litigation Authority said.
Its annual review found that the number of claims in England went up by 1,816 between March 2013 and March this year - from 10,129 to 11,945.
The body has set aside a provisional £10.5 billion to settle claims which have been notified to the NHS but are not yet resolved and claims that have been resolved over the last financial year.
A spokeswoman said: "A rise in clinical negligence claims by almost 18% over the last year is primarily due to new claimant solicitor firms entering the clinical negligence market and as a result of receiving significant numbers of claims funded by historic no-win no-fee agreements signed before April 1 2013.
"Until March 2013, these agreements allowed claimant solicitors to charge up to a 100% success fee on their costs if a claim was successful.
The NHS Litigation Authority, which indemnifies NHS organisations in England against claims, said that almost half (44%) of clinical claims where care had not been negligent were settled without paying damages, saving the NHS over £1.3 billion.
It also boasted a further £75 million in savings over the last year achieved by "robustly challenging excessive costs" charged by claimant solicitors.
Chief executive Catherine Dixon said: "It is our priority to ensure that when a patient has been harmed by the NHS they are, to the extent we are able, compensated for the harm they suffer.
"However, we experienced a significant rise in the number of claims being brought against the NHS where the care provided was not negligent.
"We were able to resolve these claims without payment, saving the NHS more than £1.3 billion."