The data shows that just over half (57%) of UK employees believe the conditions in their job allow them to be as productive as possible, with almost half (48%) stating that there are significant barriers obstructing their performance.
Employee engagement levels have also stagnated, with less than two thirds (64%) of the UK workforce feeling engaged.
As a result, company loyalty has fallen amongst UK employees since last year, with almost a quarter (24%) of employees planning to leave their current employer within the next two years.
According to Hay Group's study, UK firms are stunting performance, under-supporting employees and holding them back from delivering their best.
While 70% of staff feel motivated to go the extra mile for their organisation, less than half (43%) of employees feel that the conditions at work are conducive to optimum productivity, while half (48%) face significant barriers to performing their job well.
Long-term commitment is a casualty of stagnating engagement and enablement, as many UK employees plan to move on.
According to Hay Group's study, almost half (45%) of the UK workforce intends to leave their employer within the next five years, with one in four (24%) UK employees intending to leave their company within two years.
Ben Hubbard, Hay Group's head of insight for Europe, said: "With the gap between employee motivation and employee enablement continuing to widen, UK firms are wasting a valuable opportunity to unlock the full productivity of their workforce.
"UK firms trying to bounce back from the recession simply cannot afford to rely on the intrinsic motivation of staff. At such a crucial time for the economy, companies need to provide the vision, leadership and support to maximise staff engagement and minimise barriers to productivity.
"There is a clear disparity between the discretionary effort UK employees are willing to invest in their firm and their ability to do so.
"If firms want to tap into this potential and drive productivity, business leaders need to understand the role they have to play in enabling high levels of performance.
"While employees have been reluctant or unable to move jobs since the recession took hold, a small improvement in the labour market is likely to provoke significant movement.
"Unfortunately, it is often the best performing, highest potential workers who are prepared to vote with their feet if the organisation doesn't give them what they need to deliver."
Hay Group examined annual engagement and enablement levels in 1,610 organisations across 46 countries, representing almost five million employees.