Research by the Liberal Democrats has shown that over 10,000 operations were cancelled due to hospital beds being unavailable in 2016, up almost 60% from two years ago.
Across 40 NHS trusts in England, the number of operations cancelled due to beds not being available has almost doubled from 6,545 in 2014 to 10,259 in 2016.
In several trusts the number of cancelled operations due to lack of beds has tripled in the last two years, including Epsom St Helier and Weston Super Mare.
Around a third of all operations cancelled were due to bed shortages.
The Liberal Democrats have pledged to invest £10bn of capital funding in the NHS over the next parliament to repair run-down hospitals, improve capacity and modernise services.
The party will also raise around £6bn a year through its landmark policy of putting a penny on income tax to rescue the NHS and social care.
Liberal Democrat Shadow Health Secretary Norman Lamb said:
“These shocking figures show the impact Conservative underfunding of the NHS is having on hospitals across the country.
“A chronic lack of beds has meant more and more operations being cancelled – often at the last minute – causing huge disruption to patients and their families.
“Tomorrow is a chance to save the NHS as we know it.
"The Liberal Democrats will invest an additional £10bn in the NHS to fix our run-down hospitals, reduce overcrowding and build a world-class health service.
“This is on top of the £6bn a year for the NHS we would raise by putting a penny on income tax."