2018 £m	2017 £m
Revenue	728.6	690.2
Cost of sales	(451.0)	(429.9)
Gross profit	277.6	260.3
Other operating income	11.6	4.5
Distribution costs	(20.2)	(21.3)
Administration expenses	(128.4)	(118.6)
Other operating expenses	(2.3)	(1.0)
Headline operating profit	138.3	123.9
Amortisation of acquired intangible fixed assets	(3.7)	(4.5)
Acquisition costs	(0.5)	–
Operating profit	134.1	119.4

Profit for the year has been arrived at after charging/(crediting):

	2018 £m	2017 £m
Net foreign exchange gain	(0.1)	–
Inventory expensed	55.6	53.0
Depreciation of property, plant and equipment	60.1	58.1
Amortisation of intangible fixed assets	5.6	6.2
Gain on disposal of property, plant and equipment	(1.7)	(0.7)
Staff costs (see note 4)	291.1	283.8
Acquisition costs	0.5	–
Impairment (gain)/loss on trade receivables	(0.2)	0.8
Impairment of fixed assets – recognised in operating profit	1.8	0.4

The analysis of auditor's remuneration on a worldwide basis is as follows:

	2018 £m	2017 £m
Fees payable to the auditor for the audit of the annual accounts	0.2	0.1
Fees payable to the auditor and its associates for other services:
The audit of the Group's subsidiaries	0.7	0.7
Total audit fees	0.9	0.8
Audit-related assurance services*	0.1	0.1
Total non-audit fees	0.1	0.1
	1.0	0.9

In addition to the amounts shown above, the auditor received fees of £7,700 (2017: £7,000) for the audit of the Group's pension schemes.

A description of the work of the Audit Committee is set out in the Audit Committee report and includes an explanation of how auditor objectivity and independence is safeguarded when non-audit services are provided by the auditor.

* This includes £0.1m (2017: £0.1m) for the review of the half year report.