More people turned to accident and emergency departments in Cornwall and the Isles of Scilly when their GP practice was closed, new figures show.
A health think tank said "a sustained and substantial refocusing of NHS resources" is required to improve access to primary care.
The figures, which come from the 2023 GP survey and saw around 760,000 patients across England complete a questionnaire about their experiences with the local GP surgery, show more and more people are turning to A&E departments when they cannot get an appointment with their GP.
Patients were asked which other NHS service they contacted when their GP practice was closed. Of the 175,000 respondents, 33.5% said they contacted A&E.
It meant the number of people turning to A&E when their local surgery was shut has risen by more than 30% in two years.
In the NHS Cornwall and the Isles of Scilly Integrated Care Board area, 307 of 1,207 people (25%) said they contacted A&E when their GP practice was closed – up from 24% the year before.
In 2021, when the question was first included in the GP survey, 19% of patients said they contacted A&E.
Every area in the country has seen a rise in people turning to A&E when their GPs are closed over the last two years.
Beccy Bird, senior fellow in health policy at think tank The King's Fund, said despite GP practices delivering more appointments, demand still outstrips capacity.
Ms Bird added: "Really improving access to primary care will take a sustained and substantial refocusing of NHS resources on primary care, supporting the expansion of the workforce, consistent and coherent engagements with patients and communities, and a continuing and relentless focus on shrinking the gap between demand and capacity."
The figures come as the public's satisfaction levels in GP surgeries fell to a record low in 2023, with 71% of patients rating the service as "good" or "very good".
Similarly, there was record low satisfaction among patients regarding making an appointment, speaking to someone at their practice on the phone, and appointment times.
In Cornwall and the Isles of Scilly, 61% said the process of making an appointment was 'good' or 'very good', while 55% said it was 'easy' or 'very easy' to speak to someone on the phone.
A further 59% were satisfied with the appointment times available.
A Department of Health and Social Care spokesperson said GPs "will always be there for their patients", and people can use the NHS 111 helpline for anything urgent that is not an emergency.
They said: "Capacity in general practice is increasing with more than 160,000 additional appointments per working day, 2,000 additional doctors and 31,000 extra staff including nurses and physiotherapists providing direct patient care and delivering for patients.
"Our Primary Care Recovery Plan also includes £240 million funding to make it easier to book appointments and we expect all practices to have a digital phone system in place by April 2024, to help beat the 8am rush."