0000001 - Document - Cover link:presentationLink link:calculationLink link:definitionLink 9952151 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS link:presentationLink link:calculationLink link:definitionLink 9952152 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) link:presentationLink link:calculationLink link:definitionLink 9952153 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) link:presentationLink link:calculationLink link:definitionLink 9952154 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) link:presentationLink link:calculationLink link:definitionLink 9952155 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (UNAUDITED) link:presentationLink link:calculationLink link:definitionLink 9952156 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) link:presentationLink link:calculationLink link:definitionLink 9952157 - Disclosure - Basis of presentation link:presentationLink link:calculationLink link:definitionLink 9952158 - Disclosure - Summary of significant accounting policies link:presentationLink link:calculationLink link:definitionLink 9952159 - Disclosure - Revenue link:presentationLink link:calculationLink link:definitionLink 9952160 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) link:presentationLink link:calculationLink link:definitionLink 9952161 - Disclosure - Goodwill link:presentationLink link:calculationLink link:definitionLink 9952162 - Disclosure - Intangible assets link:presentationLink link:calculationLink link:definitionLink 9952163 - Disclosure - Fair value measurements link:presentationLink link:calculationLink link:definitionLink 9952164 - Disclosure - Restructuring link:presentationLink link:calculationLink link:definitionLink 9952165 - Disclosure - Operating leases link:presentationLink link:calculationLink link:definitionLink 9952166 - Disclosure - Bank credit lines, loan facilities and notes link:presentationLink link:calculationLink link:definitionLink 9952167 - Disclosure - Derivatives link:presentationLink link:calculationLink link:definitionLink 9952168 - Disclosure - Income taxes link:presentationLink link:calculationLink link:definitionLink 9952169 - Disclosure - Net income per ordinary share link:presentationLink link:calculationLink link:definitionLink 9952170 - Disclosure - Share-based awards link:presentationLink link:calculationLink link:definitionLink 9952171 - Disclosure - Share capital link:presentationLink link:calculationLink link:definitionLink 9952172 - Disclosure - Business Segment and Geographical Information link:presentationLink link:calculationLink link:definitionLink 9952173 - Disclosure - Subsequent events link:presentationLink link:calculationLink link:definitionLink 9954471 - Disclosure - Summary of significant accounting policies (Policies) link:presentationLink link:calculationLink link:definitionLink 9954472 - Disclosure - Summary of significant accounting policies (Tables) link:presentationLink link:calculationLink link:definitionLink 9954473 - Disclosure - Revenue (Tables) link:presentationLink link:calculationLink link:definitionLink 9954474 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) (Tables) link:presentationLink link:calculationLink link:definitionLink 9954475 - Disclosure - Goodwill (Tables) link:presentationLink link:calculationLink link:definitionLink 9954476 - Disclosure - Intangible assets (Tables) link:presentationLink link:calculationLink link:definitionLink 9954477 - Disclosure - Fair value measurements (Tables) link:presentationLink link:calculationLink link:definitionLink 9954478 - Disclosure - Restructuring (Tables) link:presentationLink link:calculationLink link:definitionLink 9954479 - Disclosure - Operating leases (Tables) link:presentationLink link:calculationLink link:definitionLink 9954480 - Disclosure - Bank credit lines, loan facilities and notes (Tables) link:presentationLink link:calculationLink link:definitionLink 9954481 - Disclosure - Derivatives (Tables) link:presentationLink link:calculationLink link:definitionLink 9954482 - Disclosure - Income taxes (Tables) link:presentationLink link:calculationLink link:definitionLink 9954483 - Disclosure - Net income per ordinary share (Tables) link:presentationLink link:calculationLink link:definitionLink 9954484 - Disclosure - Share-based awards (Tables) link:presentationLink link:calculationLink link:definitionLink 9954485 - Disclosure - Business Segment and Geographical Information (Tables) link:presentationLink link:calculationLink link:definitionLink 9954486 - Disclosure - Summary of significant accounting policies - Schedule of Finite-Lived Intangible Assets (Details) link:presentationLink link:calculationLink link:definitionLink 9954487 - Disclosure - Revenue - Schedule of Disaggregation of Revenue (Details) link:presentationLink link:calculationLink link:definitionLink 9954488 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) - Schedule of Accounts Receivables and Unbilled Revenue (Details) link:presentationLink link:calculationLink link:definitionLink 9954489 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) - Schedule of Unbilled Services and Unearned Revenue or Payments on Account (Details) link:presentationLink link:calculationLink link:definitionLink 9954490 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9954490 - Disclosure - Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9954491 - Disclosure - Goodwill - Schedule of Goodwill (Details) link:presentationLink link:calculationLink link:definitionLink 9954492 - Disclosure - Goodwill - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9954493 - Disclosure - Intangible assets - Schedule of Finite-Lived Intangible Assets (Details) link:presentationLink link:calculationLink link:definitionLink 9954494 - Disclosure - Intangible assets - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9954495 - Disclosure - Fair value measurements - Measurement of Fair Value of Major Asset and Liability classed (Details) link:presentationLink link:calculationLink link:definitionLink 9954496 - Disclosure - Fair value measurements - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9954497 - Disclosure - Restructuring - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9954498 - Disclosure - Restructuring - Summary of Restructuring Charges (Details) link:presentationLink link:calculationLink link:definitionLink 9954499 - Disclosure - Restructuring - Summary of Details of Movement in Restructuring Charges (Details) link:presentationLink link:calculationLink link:definitionLink 9954500 - Disclosure - Operating leases - Schedule of Lease Costs (Details) link:presentationLink link:calculationLink link:definitionLink 9954501 - Disclosure - Operating leases - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9954502 - Disclosure - Operating leases - Schedule of Operating Lease Maturity (Details) link:presentationLink link:calculationLink link:definitionLink 9954502 - Disclosure - Operating leases - Schedule of Operating Lease Maturity (Details) link:presentationLink link:calculationLink link:definitionLink 9954503 - Disclosure - Bank credit lines, loan facilities and notes - Schedule of Long-term Debt Instruments (Details) link:presentationLink link:calculationLink link:definitionLink 9954504 - Disclosure - Bank credit lines, loan facilities and notes - Schedule of Contractual Maturities of Debt (Details) link:presentationLink link:calculationLink link:definitionLink 9954505 - Disclosure - Bank credit lines, loan facilities and notes - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9954506 - Disclosure - Bank credit lines, loan facilities and notes - Schedule of Principal Payments on Debt Instruments (Details) link:presentationLink link:calculationLink link:definitionLink 9954507 - Disclosure - Bank credit lines, loan facilities and notes - Schedule of Movement on Debt Instrument (Details) link:presentationLink link:calculationLink link:definitionLink 9954508 - Disclosure - Derivatives - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9954509 - Disclosure - Derivatives - Effect of Derivative Financial Instruments on Statement of Financial Position (Details) link:presentationLink link:calculationLink link:definitionLink 9954510 - Disclosure - Income taxes - Schedule of Components of Tax (Details) link:presentationLink link:calculationLink link:definitionLink 9954511 - Disclosure - Income taxes - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9954512 - Disclosure - Net income per ordinary share - Schedule of Reconciliation of Number of Shares Used in Computation of Basic and Diluted Net Income Per Ordinary Share (Details) link:presentationLink link:calculationLink link:definitionLink 9954513 - Disclosure - Net income per ordinary share - Schedule of Reconciliation of Net Income Attributable to the Group (Details) link:presentationLink link:calculationLink link:definitionLink 9954514 - Disclosure - Share-based awards - Summary of Stock Option Activity (Details) link:presentationLink link:calculationLink link:definitionLink 9954515 - Disclosure - Share-based awards - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9954516 - Disclosure - Share-based awards - Schedule of Weighted Average Fair Values and Assumptions Used (Details) link:presentationLink link:calculationLink link:definitionLink 9954517 - Disclosure - Share-based awards - Summary of RSU and PSU Activity (Details) link:presentationLink link:calculationLink link:definitionLink 9954518 - Disclosure - Share-based awards - Schedule of Non-Cash Stock Compensation Expense (Details) link:presentationLink link:calculationLink link:definitionLink 9954519 - Disclosure - Share capital (Details) link:presentationLink link:calculationLink link:definitionLink 9954520 - Disclosure - Business Segment and Geographical Information - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9954521 - Disclosure - Business Segment and Geographical Information - Schedule of Distribution of Revenue by Geographical Area (Details) link:presentationLink link:calculationLink link:definitionLink 9954522 - Disclosure - Business Segment and Geographical Information - Schedule of Distribution of Income from Operations by Geographical Area (Details) link:presentationLink link:calculationLink link:definitionLink 9954523 - Disclosure - Business Segment and Geographical Information - Schedule of Distribution of Depreciation and Amortization by Geographical Area (Details) link:presentationLink link:calculationLink link:definitionLink