Many people are going without seeing their GP because they find it too difficult to make an appointment, a poll has found.
More than a third (36%) of people surveyed said they have gone without seeing their doctor in the past 12 months because they could not get through on the phone, Octopus Healthcare said.
About one in five (19%) said they have gone without seeing their GP more than once in the past year, the Censuswide poll of more than 2,000 over-16s in the UK found.
Octopus Healthcare chief executive Benjamin Davis said: "GP practices up and down the country are doing a fantastic job, often in challenging circumstances, as they strive to meet the diverse needs of patients.
"Sadly, it's clear that millions of people are having to go without seeing their GP because they can't get through to make an appointment. This is just one of a complex set of pressures on our health system; we need innovative solutions to fix the problem.
"Merging GP practices together on a local level in modern, quality buildings is a key part of the solution.
"Larger practices and better-equipped buildings help attract and retain staff, and allow practices to use new technology such as booking systems so that patients can get through on the phone. This will ultimately help cut waiting lists and improve the range and quality of services on offer to patients."
Paul Smith manages Princeway Health Centre in Frodsham, Cheshire, which opened in 2011 through partnering with Octopus Healthcare.
He said: "We now look after more than 17,000 patients in Cheshire and have over 60 members of staff at our practice, including 11 GPs and seven nurses as well as health care assistants, phlebotomists and receptionists.
"We also have an integrated community team of district nurses, community matrons and social workers all working together from the same office, and this was made possible from the planning stages of the building.
"Our modern surgery means we can bring more services such as blood tests and physiotherapy closer to our patients through a single building. But excellent service for our patients starts from the initial phone call.
"Our telephone and clinical IT systems are completely joined up. We have over 50 phone lines and a dedicated phone room, allowing us to take between 500 and 700 calls on a typical morning, while freeing up reception staff to help people in person."
Octopus Healthcare, part of Octopus Group, manages healthcare properties in the UK and Ireland, working with the NHS to provide landlord services to more than 150 medical centres.
An NHS England spokesperson said: "This tiny and statistically insignificant survey is basically a marketing device by a property services company looking to drum up business for itself.
"What's more, during the course of the next year, the whole of the country will for the first time be able to get evening and weekend GP appointments, backed by £200 million of new investment."