A "silver exodus" of valuable workers is exacerbating the UK's recruitment crisis - but experts suggest that older employees may just be reacting to ageism in the workplace.

The government is wringing its hands over how to address a hidden phenomenon of "economically inactive" workers who are not registered as unemployed.

But a report by Robert Walters recruitment company suggests employers' attitudes may be driving away older workers - with 62% of over 55s overlooked for promotion within their current company - as well as lacking training and opportunities.

Chancellor Kwasi Kwarteng is trying to tackle the over-50s workplace exodus - which began during the pandemic and has continued - through his Growth Plan. Jobseekers aged 50-plus are to be given extra time with jobcentre work coaches to help them return to the jobs market.

He is concerned because the trend is having an effect on the UK's faltering finances. Getting older workers back into the workforce would help the UK's Gross Domestic Product (GDP), the government believes.

"Rising economic inactivity in the over 50s is contributing to shortages in the jobs market, driving up inflation and limiting growth. Returning to pre-pandemic activity rates in the over 50s could boost the level of GDP by 0.5 to 1 percentage points," said the Treasury department.

According to the Institute of Fiscal Studies, the number of people in paid work in the first quarter of 2022 was 32.6m - 500,000 lower than its pre-pandemic peak of 33.1m in the three months to February 2020. This fall has been concentrated among 50 to 69-year-olds, it says.

But Robert Walters recruitment firm said over 50s were finding it tough in the workplace. Despite a "fiercely competitive" hiring market, they are being overlooked in favour of much younger and less experienced workers, it said.

Its Diversity and Inclusion Report found two in three white collar workers over the age of 55 have been overlooked for a promotion in the last year – compared to about a third (37%) of professionals under the age of 30, who have received a promotion. One in five feel "misunderstood" by their employer - while their higher pension contributions is a leading factor in enabling them to retire early. Around 45% of over 50s are actively looking for part-time, freelance roles over full-time work.

Robert Walters pointed out that since 1971, economic inactivity had been declining in the UK - but shot back up during the pandemic so that more than a fifth (21.4%) are now classed as "economically inactive". The next generation is also better-placed to retire early, it suggests. Boomers (56-75 years) and Gen-Xers (41-55 years) receive higher pension contributions as a key workplace benefit compared to Millennials (26-40 years) and Gen-Z (up to 25 years).

According to its survey, the three main challenges for over-50s progressing in their career are the lack of opportunities (41%), difficulty in balancing work and personal lives (33%) and lack of training (21%).

Robert Walters' UK boss Chris Poole said: “With professional job vacancies continuing to climb at near-record levels, causing a severe skills shortage, we cannot afford to overlook such a crucial part of our workforce.

“Workers over the age of 50 come with bags of experience both professional and personal, and have a well-sought after resilience to economic upheaval considering the number of financial or political changes they have weathered in their career.”

Dame Sharon White - boss of retail chain John Lewis - is among employers leading the charge to get more older workers back into the workplace. She wants some of the 1m mostly over-50s who left jobs during the pandemic to be encouraged back to tackle the labour shortage.

“Regardless of what is happening coming out of Covid, if the labour market is that tight, if we continue to have far fewer people in work – or looking for work – you have inevitably got more inflation and wage inflation,” she said.

Mr Poole said employers should be focusing on resolving issues deterring over-50s from work. "They need to compete with the allure of early retirement and more casual work options by implementing skills-sharing schemes to help stimulate promotion opportunities for mature workers, or establishing more accessible hybrid-working options to accommodate the need for flexible working,” he said.

Vicky Webber, who heads up HR consultancy at regional accountancy firm Lovewell Blake, said older workers should be embraced by this region's employers.

“At a time when employers are facing a widespread skills shortage, they can ill afford to lose out on the skills and experience of their older workers. A 50 year-old employee could have the best part of two decades of their career ahead of them. Ignoring that huge potential would be a big mistake," she said.

However, with the onset of a cost-of-living crisis signs suggest that they could be returning anyway, she suggested.

“That is good news for employers. That cohort represents a massive talent pool at a time when many are struggling to find the right people to fill vacancies," she said.

“I think there could be an element of assumptions being made by employers about older staff members, without having a conversation with them about what their aspirations are. This may be because employers wrongly assume that older workers no longer want to keep progressing in their careers, or else through fear of having that conversation in the first place.

“Either way, at a time of a significant skills shortage, no employer can afford to miss out on the skills, experience and work ethic that many employees aged over 50 can offer.”

Charlotte Bate, director of regional HR consultancy MAD-HR, believes business leaders in East Anglia are increasingly aware of the benefits older workers bring.

“Our clients are welcoming the opportunity to have a team with a great breadth of insights and skills, and therefore, they acknowledge and appreciate that those who are older in age typically do bring more developed knowledge in their field, honed professional abilities, and to some extent, a robustness and agility which may have come from what they have previously encountered in a workplace," she said.

But there was an adjustment during the pandemic, she acknowledged, with older employees assessing their work-life balance - and some choosing to retire.

“Against this backdrop, it’s really important that employers ensure their roles are attractive to those of all ages and life responsibility, and that they are regularly communicating with staff about what barriers they perceive in progressing professionally in order that these can be addressed," she said.

“We would also advise business owners to have clear and considered policies and procedures around the recruitment and promotion of all staff regardless of age, and in addition, that they stay abreast of legislation and advice as and when it is updated by the government in respect of all employees."