Banking experts estimate that up to 5bn may be sitting unclaimed in UK bank accounts that have gone 'dormant'. What does this mean, and could you be entitled to a share in this huge amount of idle money?
A bank account goes dormant when, in the words of the British Bankers' Association, a bank and a customer 'lose touch with each other'. What this usually means in practice is that a customer has either passed away or moved house, and the bank haven't been told and are unable to locate the account holder some time later.
If there are no transactions on an account over a period of around 12 months, the bank will write to the account holder at the last known address to ask them if they wish to keep the account open. If no reply is received, then the bank will change the status of the account to 'dormant'. This means that from now on, no statements, chequebooks or other correspondance will be sent out to the customer.
The money in the account will still earn interest at whatever the normal rate of that account is, and the bank will still keep track of the account balance and keep a record of the last known address of the holder.
There are two main reasons for an account being made dormant. The first and most obvious one is to save the banks the administration costs of sending out statements and the like when there is no activity on the account from month to month (other than that initiated by the bank itself, such as interest payments).
The more important reason however is to guard against identity fraud. If a bank continues to send statements to an address when the account holder is no longer there to receive them, it is all too easy for these documents to end up in the hands of fraudsters, who could use the sensitive information they contain to begin a campaign of ID theft.
Most dormant accounts will have very small balances, but some will inevitably contain a substantial sum, often those belonging to someone who has passed away. If you think you may be entitled to money held in a dormant account, you can make a claim by filling in a form available from the bank in question.
You will need to give your reasons for making a claim, such as that the account belonged to a close relative whose estate was passed to you. You will also need to prove your own identity, and your connection to the original account holder if applicable.
If the bank don't agree that you're entitled to take over the account, you have the right to pursue an appeal, where your claim is re-examined. If the appeal fails, you can take your claim to the Financial Ombudsman Service, whose decision is final and binding.

Nicholas Hunt is a contributing writer at 1Stop Finance, where you can read more about CCJs and other aspects of bad credit finance.