A new law which means workers no longer have to retire on the grounds of their age comes into full swing today.

The measures are expected to help both the young and old whose age leads them to being treated differently at work.

But the move has met with a mixed reaction from pensioners and is predicted to cause widespread confusion among employers and staff.

Jill Barnes, 70, who runs Oxfordshire-based employment agency 40+ Recruitment, said: "I approve of it in principle and most of the attention has been on older people.

"But I think it will have a real impact on the 16 to 25-year-olds. At the moment employers ring us and ask for people over the age of 30 but that can't happen now."

Mrs Barnes' company has been going for 11 years and has more than 1,000 people on its books, about 100 of whom are over 65.

The new legislation has meant she has had to remove her company slogan "for the mature applicant," but she refuses to change the name of the company altogether.

It is areas such as this which could lead to major problems in the workplace, as both bosses and workers struggle to come to terms with the implications of the new laws.

Clare Fowler, senior solicitor with lawyers Blake Lapthorn Linnell, based in Botley, said it could now be an offence under the act to reward staff for long service or even to present an older worker with a birthday cake with a lot of candles on it.

She added: "If you make a joke about someone being 'past it' then it could be conceived as harassment.

"Job adverts specifying several years experience could also be illegal."

And if bosses fall foul of the new law, then they could be forced to pay thousands of pounds in compensation, which is "untapped" for loss of earnings related to discrimination.

The regulations will end age discrimination in terms of recruitment, promotion and training, ban unjustified retirement ages of below 65 and remove the current age limits for unfair dismissal and redundancy rights.

Claire Prosser, policy executive at the Oxfordshire Chamber of Commerce, said: "We support the legislation. With the ever-changing age demographic, it is crucial for a business to make the best use of its employees, both young and old.

"But the Government needs to provide clear and concise advice to businesses to allow them to comply."

And for some the prospect of working beyond retirement age is not easily understood.

Oxford pensioners' champion Bill Jupp, 74, who retired at 62, said: "If people doing factory jobs want to work longer, then they are barmy.

"There is so much more in life to discover and you don't find that until you are retired."