Note2017
£000
2016
£000
Underlying profit before tax20,49716,002
Separately disclosed items within administrative expenses
IFRS2 share based payment charge22(1,512)(1,687)
Acquired intangible amortisation12(1,273)(974)
Net acquisition costs32(264)
Profit on sale of fixed assets195
Costs on exercise of executive share options(567)
Profit before tax17,34013,077
Note2017
£000
2016
£000
Underlying EBITDA22,86818,150
Separately disclosed items within administrative expenses
IFRS2 share based payment charge22(1,512)(1,687)
Net acquisition costs32(264)
Profit on sale of fixed assets195
Costs on exercise of executive share options(567)
EBITDA20,98416,199
Acquired intangible amortisation(1,273)(974)
Depreciation and non-acquired amortisation(1,850)(1,357)
Operating profit17,86113,868

There were no separately disclosed items in 2017 (2016: £nil) other than the amounts detailed above.

During the period the IFRS2 charge decreased slightly due to the acceleration in the prior year of the 2014, 2015 and 2016 Deferred Equity Bonus charges for retiring Directors, offset by a charge for the 2017 Deferred Equity Bonus scheme for Directors and the addition of a new Deferred Bonus Award scheme for senior managers. £1.1m (2016: £1.6m) relates to the Deferred Equity Bonus scheme for Directors of which £0.1m (2016: £0.8m) relates to retiring Directors. £0.3m (2016: £nil) represents the charge for the Deferred Bonus Award scheme for senior managers. The remaining £0.1m (2016: £0.1m) relates to the SAYE scheme.

The increase in the acquired intangible amortisation charge is primarily due to the acquisition of Kuhlmann in the prior year now having a full year effect.

During the year the remaining 2m options granted under the 2009 executive share option scheme were exercised. The Company incurred £0.6m of employer's National Insurance in relation to these exercises and the acceleration of the 2014, 2015 and 2016 Deferred Equity Bonus awards.

Obsolete plant and machinery was sold in our Italian manufacturing company Viteria Italia Centrale. The profit recorded on this sale was £0.2m.

Management feel it is appropriate to remove the one off costs and certain non-trading items discussed above to better allow the reader of the accounts to understand the underlying performance of the Group. Further reconciliations of underlying measures to GAAP measures can be found in note 34.