The news comes just months after the Government released its voluntary code of practice on age diversity, to encourage employers to base staffing decisions on ability rather than age.

In September the Employers Forum on Age exposed the code as ineffective by publishing figures that showed two out of three employers have no intention of changing the way they recruit staff.

The figures also show that eight million people have experienced age discrimination at work, and that more than twice as many workers in the 25 to 34 year old age group receive training than their older colleagues.

The younger age category also get paid on average £1,250 more each year in administrative, secretarial and IT positions, despite older workers having more experience. The greatest discrimination is found in the retail sector, where 25 per cent of workers are held back because of age.

However, three quarters of employers interviewed said that a jobseeker of any age who could prove their worth with a training certificate would be more likely to beat the system and secure a job or promotion.

Group operations director at Pitman, James O'Brien, said: "It's often a vicious circle for off-peak employees as they need to prove their value with qualifications, but employers are simply not investing in their skills.

"People who take a training course outside of work show enthusiasm as well as confidence, but employers must be responsible for training.

"In ten years time a quarter of our workforce will be over 50. It's also about recognising the importance of life skills such as confidence, intuition and common sense."