Patients missed a record number of outpatient appointments at Surrey and Borders Partnership Trust last year, new figures show.
It comes as the number of missed appointments across England topped 8 million for the first time in 2022-23.
The Patients Association said it would like to see "the health service be more curious and compassionate" about patients' absence.
NHS England figures show patients did not attend 31,470 outpatient appointments at Surrey and Borders Partnership NHS Foundation Trust in 2022-23 – up from 21,035 the year before, and the highest number since comparable records began in 2006-07.
It accounted for 7% of the 440,480 total appointments scheduled.
Nationally, a record 8 million of 124.5 million appointments (6.4%) were missed. It is the highest proportion of missed appointments since 2017-18, when 6.7% went unattended.
The Patients Association said there are 8 million different stories behind the missed appointments, and called on healthcare professionals to be "curious" about why patients are absent.
Rachel Power, chief executive of the Patients Association, said many patients who miss appointments are at risk of health inequalities, and urged the NHS to be compassionate.
She said the NHS should focus on making it easier for patients to get to an appointment, with many unable to attend due to caring responsibilities, travel difficulties, or not receiving a reminder if the appointment was booked a long time before.
The figure also showed hospitals cancelled 12.1 million outpatient appointments across the country – a rise of 4% on the year before, and the highest figure since records began, excluding 2020-21, which was affected by the coronavirus pandemic.
Of these, 12,295 were cancelled by Surrey and Borders Partnership Trust.
There were 95.9 million attendances nationally, up on the last two years but slightly below pre-pandemic levels.
Meanwhile, patients contacted hospitals and cancelled 7.9 million appointments, also down on before Covid-19.
At Surrey and Borders Partnership Trust, 14,650 appointments were cancelled by patients, while there was a total of 374,600 attendances.
An NHS spokesperson said the service is treating record numbers of patients and dealing with ongoing industrial action.
They added: "There are many reasons why patients miss appointments, and so our main message is always it is vital people seek care when they need it.
"But if patients are unable to attend for any reason, we would ask them to let us know so their appointment can be filled by another patient who needs it."