Randstad claims that with a population of 74.5 million, in 2050 the UK will require a workforce of 35.4 million to meet demand.
However, with a pool of just 45.1 million people (60% of the population) forecast to be eligible to work in 2050, even if the employment rate matches pre-downturn levels of 71%, an ageing population will leave the UK with only 32.3 million people in employment - 3.1 million short.
The data shows the UK is suffering skills shortages across many sectors with migration one of the key reasons for the deficiency. It shows since 2007, work-related emigration from the UK has risen 16% while work-related immigration has fallen 24% over the same period.
It claims the combination of poor economic performance and changes to immigration policy have made the UK a less attractive place to work for the world's most talented professionals and skilled tradespeople.
Mark Bull, UK chief executive, Randstad, said: "If the UK economy is to grow and overcome the difficulties of the last few years then it requires a strong workforce capable of meeting demand.
"Our projections are conservative but they still portray a worrying scenario for the country over the coming decades. With an ageing population, we need to ensure we are open for business and welcoming talent from around the world to bolster our workforce."
Bull added: "Many businesses and institutions in the UK need highly skilled staff in order to grow their business and business growth is exactly what UK PLC and the economy requires both short term and long term. Unfortunately, countless businesses simply cannot find these staff in the domestic market and when the best talent isn't available on your doorstep you have to look further afield.
"The Government has proved in the appointment of Mark Carney as the next governor of the Bank of England that sometimes the best candidates are from overseas. We must ensure this approach is allowed to run smoothly across the entire workforce where necessary to plug vital skills gaps, not just at the very top."
In November 2012 HR magazine hosted a live web TV debate on the skills gap in the UK. If you missed it you can now still register for free and watch it back on-demand.
To register and watch the debate click here
