ARE you one of the estimated 500,000 women who are owed at least £1 billion in unpaid state pension? A Timesinvestigation this month revealed that hundreds of thousands of women are being short-changed because of bungles by the Pensions Service in calculating home responsibilities protection (HRP).

To find out whether you are affected and what measures you may be able to take to rectify the situation, read our Q&A below.

What is HRP?

It is a device to boost the state pension of parents (mostly women) who stop work to bring up a family. It has been available since April 1978 to parents receiving child benefit for children under 16. It can also apply to foster parents or those who care for an ill or disabled person.

How does it work?

HRP reduces the number of years of national insurance contributions (NICs) that you need to have notched up to qualify for a full state pension. For example, if a woman accrued 20 years of HRP, this would cut the number of qualifying years needed for a full pension from 39 (the current requirement) to 20.

Who can qualify for HRP?

Women born before April 5, 1950, or men born before April 5, 1945.

How many people could be missing out on a higher pension because of the failure to include HRP?

A six-month investigation by The Times, involving parliamentary questions submitted by the Liberal Democrats and number-crunching by Grant Thornton, the accountant, indicates that the figure could be as high as half a million. The average amount owed is estimated to be several thousand pounds.

I was bringing up young children after April 1978 but continued working and paid the married woman’s reduced rate of NICs. Do I qualify for HRP?

No, but a spokeswoman for the Department for Work and Pensions adds: “You could qualify for HRP if you had been working and paying the married woman’s reduced rate and then took at least two full tax years off to look after your children. You would need to have paid full-rate contributions when you returned to work.”

How do I find out if I am not receiving my proper pension entitlement?

You should contact the Pensions Service. If you are over 60 or within four months of retirement, the number is 0845 6060265. Those already in retirement should ask if HRP has been taken into account when calculating their pensions.

Those within four months of retirement should ask for a BR1 form, also available at www.thepensionservice.co.uk. The form is a 16-page document that requests your national insurance number and asks about various benefits that you may have received. However, Mike Warburton, of Grant Thornton, says: “Do not be put off because the form does not mention HRP at all. The form is relevant, so fill it out and then follow up with a query to the Pension Service.”

If you are not in the above categories, call 0845 3000168 for a pension forecast and have your national insurance number ready.

Is there anything else I should be doing?

You could contact Steve Webb, the Liberal Democrat MP, who is compiling a dossier of people who believe that they may qualify for additional pension payments thanks to HRP. He wants to hear from women who are now drawing a state pension that is less than the full rate and who saw no mention of HRP in their pension paperwork and who spent some time after 1978 in receipt of child benefit and not paying NICs.

Mr Webb will put a number of sample cases to the Government to discover if individual women are missing out. He also hopes it will serve as a pointer to the size of the problem. He can be e-mailed at webbs@parliament.uk, or you can write to him at House of Commons, London SW1A 0AA.