Bungling tax officials under fire for losing the country's child benefit details have messed up again by sending personal details to the wrong addresses in Oxfordshire.

Grandad Ron Leaver and mum-of-three Tracey Giles were stunned to receive letters from HM Revenue and Customs containing child benefit and national insurance numbers meant for other people.

Mr Leaver, 70, from Merton near Bicester, received more than a dozen letters over a three-month period that were intended for Buckinghamshire County Council.

They included the names and NI numbers of former council employees. One even contained a cheque for £2,000.

It appears HMRC was under the impression that the local authority, whose headquarters are in Aylesbury, was in fact based 18 miles away at a private house in a small Oxfordshire village.

Mr Leaver, who received the letters between August and October despite pointing out the mistake to officials, told the Oxford Mail: "It absolutely amazes me that anyone in their right mind should think someone who lives in Oxfordshire is the address for Buckinghamshire County Council.

"I'm disgusted with the situation. No one has been able to tell me why they did this. If it's happening to me is it happening to other people? It's an absolute shambles."

More than 72,000 families in Oxfordshire have been caught up in the Revenue's loss of two discs containing the personal details of child benefit claimants in the worst security lapse in British history.

In a further embarrassing blow for the HMRC, it emerged that housewife Tracey Giles, from Hempton, near Deddington, was sent a letter meant for a Tracey Mason.

The letter, an apology for the missing data discs, contained the NI and child benefit numbers of the intended recipient, whose true whereabouts remain a mystery.

HMRC have now had to issue an apology for sending Ms Giles the wrong apology letter.

Ms Giles, who received the letter on Monday, said: "I now know Tracey Mason's child benefit number and National Insurance number and I'm worried someone has got a letter with my NI and child benefit number on them.

"I find it unbelievable. Why are they still getting the wrong letters and wrong names? It's quite astonishing."

The latest blunders will intensify the pressure on HMRC, which is struggling to salvage its reputation after losing the two data discs.

Tony Baldry, Conservative MP for Banbury, said: "Both these instances demonstrate that there's a systemic failure in Revenue and Customs."

HMRC said the two cases were under investigation and reminded claimants who had moved house to alert the Child Benefit Office to update their details.

A spokesman said: "We apologise for any inconvenience caused. We are currently writing to over seven million child benefit claimants. Letters are still being sent, so people shouldn't worry if they haven't yet received an apology."