The taxman is urging employers to double check their PAYE paperwork after receiving incorrect returns for staff members called 'A N Other' or 'Mr Cleaner', as well as employees who are apparently more than 200 years old.
As well as 507 'A N Others', employer returns for 2009/10 revealed 128 staff entered as Mr, Ms, or Mrs 'Dummy', 75 staff with the surname 'Casual', 11 'Cleaners', nine 'Workers' and six 'Students'.
824 employees had the surname 'Unknown' and 572 people's surnames only included the letter 'X', ranging from 'Mr X' to 'Mrs XXXXXX'.
Her Majesty's Revenue and Customs (HMRC)'s director of customer operations Jim Harra said: "Most employers get their PAYE returns right. The few who don't can cause problems for their employees, for example, incorrect deductions of tax. Around 80% of errors in employee data are due to an incorrect name, date of birth or national insurance number - straightforward information that can be collected and checked quite easily.
"So, whether you are employing 'Mr or Mrs J Smith' - or even 'Mr or Mrs A N Other', please use the full and official name on your PAYE paperwork. First names are very important, especially for common surnames. We really want employers to check that they are sending us the right details for all their employees, to make life easier for them, HMRC and their employees."
Employers are not the only ones making mistakes, however, as the HMRC announced this morning that 1m people are set to receive letters notifying them that they have paid too little tax.
HMRC has carried out an annual check to make sure that the amount of tax and national insurance deducted by employers matches its records.
The average amount owed per person is expected to be around £500 to £600, an HMRC spokesman said.