The poll commissioned by the Liberal Democrats shows of all UK adults who wanted a NHS GP or dentist appointment, 45% were unable to.

In addition, 17% of working adults say they have had to take at least one week off work while waiting for NHS treatment in the past 12 months and 21% ended up taking more than two weeks off while they waited for treatment.

The poll also reveals that almost 60% of Brits unable to get a NHS appointment have resorted to self-diagnosis by searching their symptoms online. The data also shows that 29% ignored their symptoms completely as they couldn't get the care they needed on the NHS.

The poll comes ahead of the Liberal Democrats opposition day, the first full opposition day for the party in 15 years, and the first opposition motion in more than six years. The Liberal Democrats will use their opposition day to highlight the crisis in the NHS and lack of support for unpaid carers.

The first Liberal Democrat motion will focus on the Carer's Allowance repayments scandal, calling on the government to write-off existing overpayments and conduct a full review of support for unpaid carers. The second motion will urge ministers to tackle the NHS crisis by improving access to GPs, NHS dentists and community pharmacists.

Liberal Democrat health and social care spokesperson Helen Morgan said: ‘The Liberal Democrats are calling for urgent investment in our health services to increase the number of GP and NHS dental appointments.

‘Fixing the crisis in our NHS is crucial to kickstarting our economy, by cutting down waiting lists and getting people back into work. The new government must make health and social care their top priority.'

Liberal Democrat Chief Whip Wendy Chamberlain added: ‘The Liberal Democrats have listened to people's concerns, and will continue to fight in Westminster to make sure the government prioritises our health and care systems after years of neglect and mismanagement.'

In response, Matthew Taylor, chief executive of the NHS Confederation, said: ‘GPs and their teams are providing millions more appointments than before the pandemic. But the primary care sector is trying to manage rising demand from patients who often have more complex or multiple conditions while parts of the country do not have enough GPs and the low financial settlement has left them doing more for less.

‘It is clear that supporting people to continue working when they can is vital for the country's economy. Part of this is tackling NHS waiting lists so that people can get back to work, but a whole-government approach is needed as only 20% of our health is determined by healthcare, with the remaining 80% affected by wider determinants.'

Recent NHS Confederation analysis with the Boston Consulting Group shows that reintegrating between half and three-quarters of people who have dropped out of the workforce for reasons of ill health since 2020 could deliver an estimated £109-177bn boost to the UK's GDP (2-3% in 2029) and unlock £35-57bn in fiscal revenue over the next five years.