As one of the last batch of teachers to begin working before the switch, Olivia Collins thought she would just make the cut-off for the old scheme.

The 26-year-old qualified in July and since September has been working as a supply teacher in primary schools in York and North Yorkshire. But her attempt to join the pension scheme before the end of the year was rebuffed.

“I thought I would be able to opt in and pay something out of my wages into a pension,” she says. “But I was told I could not join because I was working for an agency.”

Failure to join the scheme before the end of last year means Olivia will now have to work until she is 65, instead of 60, before she can claim her full pension benefits.

“A lot of my friends have already been automatically put in, which is fine for them, but I chose to do supply and it would have been good to have known about this then,” she says. “I don’t know much about the differences between the two schemes, but I do know the earlier you start, the better.”

Changes to the pension scheme, which came into force on January 1, were agreed last May, as increased life expectancy prompted Labour to look at raising the normal pension age.

Barry Fawcett, the National Union of Teachers’ assistant secretary for salaries and pensions, was involved in the negotiations over the changes.

He says the unions aimed to produce a deal to balance the interests of existing scheme members with those of new members. Although the pension age has increased, the pension benefits are calculated at an increased rate, at 1/60th of salary per year of service instead of 1/80th, meaning the total fund on retirement should be greater.

He says the new scheme also makes it easier for teachers to take a phased retirement, working fewer hours or in a less responsible post and still claim some of their pension, at the same time as continuing to add to their pension fund.

While Olivia may have been unable to get into the old scheme, her mother Joyce has a different pension problem.

Joyce, 58, is a special needs teacher in York. She has been told she could be made redundant this year from her part-time post with the local authority, but will be unable to take her pension early as she has another part-time contract with an individual school.

“I’m not really sure how it is going to work,” she says. “I feel like I’m in limbo because I do not know what is going to happen to me.”

Barry Fawcett says there is no entitlement to pension benefits for teachers who have been made redundant, unless the employer agrees to fund the additional cost of paying the pension early.

But the new scheme does allow for phased retirement, where teachers over the age of 55 have reduced their salary by 25 per cent or more.

Under the changes, teachers can continue to work while claiming up to 75 per cent of their pension benefits.