In order for a Class 1 NICs liability to arise, a payment for motoring expenses, like any other payment, must represent ‘remuneration or profit derived from an employment’ see NIM02010.
Where mileage allowances are paid for private motoring the payments are remuneration or profit derived from an employment. They are earnings.
Where a mileage allowance is paid for business travel the
employee must profit from the payment if it is to be considered
earnings.
If a payment is a reimbursement of an actual business expense
incurred by the employee in the course of their employment, the
reimbursement is not remuneration or profit derived from the
employment and so cannot be liable for NICs.
If a payment is a round sum allowance, but the actual
business expense incurred by the employee in the course of their
employment can be identified, that expense is not remuneration or
profit derived from the employment so is not liable for NICs. Any
amount that cannot be identified as a business expense is earnings
and should be included in gross pay with any other earnings paid in
the same earnings period.
Like other business related travelling expenses, the
legislation covering mileage allowances to 5 April 2002 is
regulation 25 of the Social Security (Contributions) Regulations
2001 and, in particular,
Liability for Class 1 NICs arises:
In relation to mileage allowances generally, whether or not they
are based on a mileage rate, employers are likely to find it very
difficult to comply with the requirements of paragraph 9 of Part 8
of Schedule 3 of the SS(C)R 2001 and identify the exact profit on a
pay period basis.
This is because:
In recognition of these difficulties, an administrative
arrangement operates for NICs. The arrangements allows an employer
to calculate whether there is any profit included in the payments
he makes to employees who use their own cars for business purposes.
This arrangement allows an employer to calculate and pay any NICs
liability on mileage allowances in the appropriate earnings period.
This administrative arrangement is explained at
NIM05710.