Management has determined the operating segments based on the reports reviewed by the Chief Operating Decision Makers (CODM) that are used to make strategic decisions. The Chief Operating Decision Makers are the Executive Board of Directors who will review the operating results and forecasts to make decisions about resources to be allocated to the segments and assess their performance.

The Executive Board of Directors considers and manages the business on a geographic basis. Management manages and monitors the business based on the three primary geographic areas: North America, Europe and Asia. All geographic locations market the same class of products to their respective customer base.

The Executive Board of Directors assesses the performance of the operating segments based on net sales and operating income. Net sales for geographic segments are based on the location of the design win rather than where the end sale is made. The operating income for each segment includes net sales to third parties, related cost of sales, operating expenses directly attributable to the segment, and a portion of corporate expenses. Costs excluded from segment operating income include stock-based compensation expense, income taxes, various non-operating charges, and other separately managed general and administrative costs.

Segment assets consist primarily of property, plant and equipment, goodwill, intangible assets, inventories, trade receivables, cash and cash equivalents, derivative financial instruments and exclude tax assets.

Segment liabilities comprise trade and other current liabilities, derivative financial instruments, borrowings, accrued contingent consideration and exclude tax liabilities.

(i) Revenue

The Group derives revenue from the transfer of goods at a point in time in the following major product lines and geographical regions.

Analysis by class of customer

The revenue by class of customer is as follows:

Revenues of £27.9 million (2017: £17.0 million) are derived from a single external customer. These revenues are attributable to the semiconductor manufacturing sector.

The Group operates in the following regions and countries:

The majority of North America's revenue is generated from the United States of America.

Revenue is based on sales generated in each region or country.

(ii) Segment

The segment information provided to the CODM for the reportable segments for the year ended 31 December 2018 and prior year comparatives is as follows.

Reconciliation of segment results to profit after tax:

Capital additions comprises additions to property, plant and equipment.

* Balance is less than £100,000.

Non-current assets, other than deferred income tax assets, by countries:

Reconciliation of adjusted measures

The Group presents adjusted operating profit, adjusted EBITDA and adjusted profit before tax by making adjustments for costs and profits which management believes to be significant by virtue of their size, nature or incidence or which have a distortive effect on current year earnings. Such items may include, but are not limited to, costs associated with business combinations, gains and losses on the disposal of businesses, fair value movements, exceptional operating costs, and amortisation of intangible assets arising on business combinations. Exceptional operating costs include reorganisation costs, acquisition-related charges and similar items of a significant and a non-recurring nature.

The Group discloses adjusted EBITDA, being adjusted operating profit before depreciation of property, plant and equipment and amortisation of intangible assets. Adjusted EBITDA is broadly used by analysts, rating agencies, investors and the Group's banks as part of their assessment of the Group's performance. A reconciliation of adjusted EBITDA from operating profit is shown below.

In addition, the Group presents an adjusted profit after tax measure by making adjustments for certain tax charges and credits which management believes to be significant by virtue of their size, nature or incidence or which have a distortive effect.

The Group uses these adjusted measures to evaluate performance and as a method to provide shareholders with clear and consistent reporting. See below for a reconciliation of operating profit to adjusted EBITDA and adjusted operating profit, a reconciliation of profit before tax to adjusted profit before tax and a reconciliation of profit after tax to adjusted profit after tax.

(i) A reconciliation of operating profit to adjusted Earnings Before Interest, Taxes, Depreciation and Amortisation ("EBITDA") is as follows:

(ii) A reconciliation of operating profit to adjusted operating profit is as follows:

(iii) A reconciliation of profit before income tax to adjusted profit before tax is as follows:

(iv) A reconciliation of profit after tax to adjusted profit after tax is as follows:

1. Adjusted for tax on exceptional expense for both completed and aborted acquisitions of £0.1 million (2017: £1.1 million), one-off tax adjustment of £nil (2017: £1.3 million) and tax effect of change in US federal tax of £nil (2017: £1.3 million).