As a result of incorrect dates of birth being recorded we are seeing an increase in underpaid Employer national insurance contributions dated as far back as tax year 15/16 when the new legislation came into action.
As you will be aware from the 6th April 2015 employers who employed staff under the age of 21 years old they were no longer required to pay class 1 secondary National Insurance on earnings up to the Upper Secondary Threshold (UST).
In most cases payroll software bases this calculation using the NI Category letter selected which in this case is M or H for apprentices. The DOB is they key source of information to determine the NI Category to be applied.
It would be recommended you carry out an audit of employee data held to check you hold correct DOB for all staff and include within your on boarding process for new staff evidence of DOB by means of a passport or birth certificate to ensure you as the employer do not fall foul of underpaid contributions.