A study has suggested women and young people have been hardest hit psychologically by the Covid-19 lockdown, as MPs were told the world will be living with Covid-19 for “decades to come”.

A new study found 27% of people in the UK were experiencing clinically significant levels of psychological distress in April, compared with 19% before the pandemic.

A General Health Questionnaire (GHQ) assessing the severity of a mental health problem over the previous few weeks also showed increasing distress across the population in April.

The 12 questions included how often people experienced symptoms such as difficulties sleeping or concentrating, problems with decision-making or feeling overwhelmed.

Increases were bigger in some groups compared to others – with a 33% rise among women, 32% among parents with children under five and 37% among young people aged 18 to 24, the study published in The Lancet Psychiatry found.

Sally McManus, joint senior author of the study from City University, said: “The pandemic has brought people’s differing life circumstances into stark contrast.

“We found that, overall, pre-existing inequalities in mental health for women and young people have widened.

“At the same time, new inequalities have emerged, such as for those living with pre-school children.”

Data from the Office of National Statistics on homeschooling during the Covid-19 pandemic is due to be released on Wednesday.

Even, actually, if we have a vaccine or very good treatments, humanity will still be living with this virus for very many, many years to come

Research on how parents in Great Britain have managed working from home in addition to their parenting responsibilities is also set to be released by the agency.

Meanwhile, former Cabinet minister Damian Green has called on civil service workers to “set an example” and return to Westminster, which he said now looks like a “zombie apocalypse”.

The MP said in a column for The Sun that civil service staff working from home had led to “second-class public services and the throttling of business”.

He said the service had “had months to make its offices safe, and we have seen the ingenuity of pubs, restaurants and bars in doing the same in much less time, and sometimes with a clientele that will be much less disciplined”.

“So safe offices should now be filling up again, with workers ending those backlogs and restoring the vitality of our cities,” he added.

His call comes after Wellcome Trust director and Scientific Advisory Group for Emergencies (Sage) member Professor Sir Jeremy Farrar said the world will be living with Covid-19 for “decades to come”.

Appearing before the Health and Social Care Committee on Tuesday, Prof Farrar told MPs: “Things will not be done by Christmas. This infection is not going away, it’s now a human endemic infection.

“Even, actually, if we have a vaccine or very good treatments, humanity will still be living with this virus for very many, many years to come.”

Prof Farrar also criticised the timing of the lockdown, saying: “I believe lockdown was too late, I believe lockdown should have come in earlier.”

MPs also heard evidence from chief medical officer Professor Chris Whitty, who defended his actions over the pandemic, saying lockdown came at about the right time.

Prof Whitty also told MPs that widespread community testing earlier on in the pandemic required “an infrastructure we did not have”.

He told committee chair and former health secretary Jeremy Hunt that Sage had consistently said that more testing capacity was needed.

But he agreed that, given the capacity, it was the correct advice to stop widespread community testing on March 12.

Prof Whitty later said that ministers followed scientific advice with a “delay that was no more than you would reasonably expect”.

Meanwhile, the announcement of a pay rise for public sector workers caused controversy as nurses, care staff and social workers were excluded from the deal.

Almost 900,000 workers are set to benefit from the pay rise, with teachers and doctors seeing the largest increase at 3.1% and 2.8% respectively under measures announced by Chancellor Rishi Sunak.

However, nurses and care workers do not qualify for the raise as their pay arrangements are managed under a separate deal.