Thousands of patients are having their operations cancelled on the day of their scheduled surgery, a new report has found.
And tens of thousands are being forced to wait for longer than 18 weeks for routine operations, the authors said.
Equipment shortages, a lack of beds and scheduling errors were the main excuses given to patients for cancelling their elective surgeries on the day, the authors said.
The Patients Association warned that cancelling an operation places a "significant psychological burden" on patients.
A new report from the patient charity found that during 2015 hospital trusts across England cancelled an average of 753 operations on the day.
Its annual report Feeling The Wait found that the total number of surgeries cancelled by individual trusts ranged from eight to 3,269.
The report states: "We have grown increasingly concerned at the waits patients are facing for surgery and the amount of patients who have had their operation cancelled on the day."
It adds: "There is a significant psychological burden on patients waiting to be given a date for surgery and for patients whose surgery has been cancelled (often on the day the surgery was due to take place)."
Meanwhile the report also highlighted "substantial" increases in the number of patients who are waiting more than 18 weeks for routine operations.
"This year's report based on 2015 data shows that on the whole, waiting times are getting worse, not better," the authors wrote.
Their analysis show that the number of patients waiting for elective surgical procedures - such as hip or knee operations - over 18 weeks during 2015 was 92,739, compared to 51,388 in 2014 - a rise of around 80%.
The report is based on responses to 112 Freedom of Information requests sent to NHS Trusts across England.
And the average waiting times for five procedures - hip replacement, knee replacement, hernia, adenoid and tonsillectomies - are above 100 days, the Patients Association said.
"The Patients Association has noticed a clear, trend over recent years in the increasing time people are waiting for operations, as well as the number of people waiting longer for elective surgery," said Patients Association chief executive Katherine Murphy.
"Every day we hear from the people behind these statistics on our national helpline: individuals who are in pain, worried they will lose further mobility, or will take longer to recover when they finally get their surgery. Their family members and carers are also having to share the added uncertainty and pressure faced by patients whilst they are waiting for their operations.
"Overall, with the significant jump in waiting times, we are very concerned that relaxing the rules on waiting time targets as recently reported, will only exacerbate an already unacceptable situation for patients.
"From the patient's perspective, nothing positive can come from taking away NHS targets - it just means people could be waiting even longer as there will be little incentive for NHS providers to focus on efficiency."
In July NHS officials in England announced that hospital trusts will no longer be fined for missing key targets on waiting times and cancer as part of a bid to improve finances.
National fines for missing targets have been scrapped for at least 12 months and replaced with individual trust plans aimed at improving performance and finances.
Hospitals will no longer be fined for missing the four-hour A&E target, the 62-day target to get cancer treatment and the 18-week goal for routine operations, such as hip and knee replacements.
Health officials contested the claims by the Patients Association on the number of patients waiting more than 18 weeks for routine operations.
Health minister David Mowat said: "These claims are both unreliable and misleading. The latest official figures show that nine in 10 patients still wait less than 18 weeks for treatment, despite the fact that last year the NHS carried out 1.6 million more operations than in 2010."
He added: "Fewer than 1% of operations were cancelled on short notice - stable despite this rising activity - and the number of people waiting more than a year has dropped by nearly 18,000 under this Government."
An NHS England spokesman said: "We have significant concerns about this report which is both misleading and statistically flawed and is based on a fundamental misunderstanding of the referral-to-treatment performance standard. Waits for an NHS operation remain close to an all-time low - down from a maximum wait of 18 months over a decade ago to 18 weeks now, with the average wait less than 10 weeks.
"Last month more than nine out of 10 patients were waiting less than 18 weeks to start consultant-led treatment. We continue to make strides in cutting long waits, with the number of patients waiting over a year slashed from over 5,000 recorded in March 2012 to being in the hundreds now. In the last five years, since June 2011, the NHS has reduced the number of patients waiting more than a year for treatment by over 12,000."