I have children. Will I be affected?

Revenue & Customs (HMRC) says that your details are at risk only if someone in your family is claiming child benefit (£18.10 a week for the eldest child and £12.10 a week for each additional child). If all your children are over the age of 19 it is unlikely that your or their details are on the discs that have been lost

What is on the discs?

Parents who register for child benefit must give HMRC their name and maiden name, their national insurance number, their date of birth, their address and the full name and birth dates of the children for which they are claiming

Those who want the benefit payments paid straight into their bank account must also give all their bank details including their account number and sort code. If you are a parent or carer who receives child benefit payments your personal and bank account details are at risk

If your spouse or partner receives payments, your own bank account details should be safe, but your personal details are still at risk

Children who are receiving benefit are also at risk as their personal details are on the discs

Those who are too old to receive child benefit but have a younger sibling still receiving the payouts are also listed on the disc

My details are on the disc. What does that mean?

You are in danger of becoming a victim of identity fraud if the discs have fallen into the wrong hands. Criminals might try to access your bank account or apply for credit in your name using your personal details

What can I do to protect myself?

The banking information on the disc should not be enough to withdraw money from your account. Banks usually ask for another form of ID or personal identification number

But you should check your bank statements. If you spot unusual activity on your account, you should contact your bank immediately

The biggest danger is that fraudsters will use your personal details, such as your name and address, to apply for credit in your name. You can protect yourself against this type of identity fraud by contacting one of the three credit reference agencies:

Callcredit (www.Callcredit.co.uk , 0113-244 1555); Experian (www.Experian.co.uk ); and Equifax (www.equifax.co.uk , 0870 010 0583). These agencies offer online credit file monitoring – at a charge of between £30 and £75 a year – so you will be alerted if someone opens an account or takes out a loan in your name

The cheaper alternative is to order a copy of your credit report regularly. Each report costs about £2

You can also register with CIFAS (www.cifas.org.uk ) so that extra checks are carried out on any credit applications made in your name

Can I get a refund if a fraudster accesses my bank account?

Under the banking code, customers who are victims of fraud can get a refund from their bank or building society

What is HMRC doing to help?

Banks and building societies were told of the problem last Friday. Since then they have flagged accounts that have been affected and have monitored them for unusual activity from the date that the information went missing. They have not found any suspicious activity so far

HMRC has set up a Child Benefit Helpline on 0845 302 1444 for customers who want more detail

The banking industry has also produced a help sheet at www.apacs.co.uk