HMRC have failed to contact around 300,000 taxpayers likely to be affected by changes to next week's introduction of the high-income child benefit charge.
At least 25% of taxpayers caught by the new regime, which begins on Monday 7 January, will find themselves paying the higher rate charge and have to complete a self assessment return.
The Revenue estimates 1.1m taxpayers will be affected by the new rules, and claims it has written to about 800,000 individuals, but it has been unable to contact everyone because of incomplete data.
“There may be cases where people’s circumstances have changed – for example, their income may have increased or address may have changed – and we will not yet have up-to-date information,” said an HMRC spokesperson.
The department has run an extensive media campaign to raise awareness, and its online guidance has had more than one million hits, which “show that the message is getting through”.
The spokesperson added, “Our target audience will have seen the adverts five times on average, and there has been extensive media coverage of the change.”
The child benefit awareness ads have appeared alongside other, more prominent Revenue campaigns encouraging timely self assessment submissions and warning against tax evasion.