Thousands haven't claimed their £2,200 in savings account government set up for them

More than 670,000 remain unclaimed and untouched, according to HM Revenue and Customs.

The long-term, tax-free savings account was established with a £250 deposit from the government for every child born in the UK between September 1, 2002, and January 2, 2011.

The average amount in these forgotten accounts is now £2,212, as the government urges those aged 18-22 to claim their funds. Account holders can take control at age 16 or withdraw the money at 18 when the account matures.

Parents can contribute up to £9,000 annually without tax implications, and any income or profit doesn't affect household benefits or tax credits.

The scheme closed in 2011, so while the oldest could have claimed their funds four years ago, the youngest are only 13 and still have years before they can access their accounts.

These accounts, held by banks, building societies, or other savings providers, will continue to stagnate until the owners claim or reinvest them.

Those who know which company holds their Child Trust Fund can contact them directly to arrange their preferred outcome.

The government's website provides a for tracking down lost accounts, but you'll need your National Insurance number and date of birth to get started.

Angela MacDonald, HMRC's Second Permanent Secretary and Deputy Chief Executive, has issued a stark warning against using third-party agents to find these funds.

She cautioned: "Third-party agents are advertising their services offering to search for Child Trust Funds and agents will always charge - with one charging up to £350 or 25% of the value of the savings account.

"Using an agent can significantly reduce the amount received, is likely to take longer and customers still need to supply them with the same information they need to do the search themselves."