The calculations of the basic and diluted earnings per share attributable to the ordinary equity holders of the Company are based on the following data:
| £ Millions | 2018 | 2017 |
| Earnings | | |
Earnings for the purposes of basic and diluted earnings per share
(profit attributable to equity holders of the Company) | 30.2 | 28.3 |
| Earnings for earnings per share | 30.2 | 28.3 |
| Number of shares | | |
| Weighted average number of shares for the purposes of basic earnings per share (thousands) | 19,134 | 19,082 |
| Effect of potentially dilutive share options (thousands) | 366 | 306 |
| Weighted average number of shares for the purposes of dilutive earnings per share (thousands) | 19,500 | 19,388 |
| Earnings per share from operations | | |
| Basic | 157.8p | 148.3p |
| Basic adjusted* | 176.1p | 149.4p |
| Diluted | 154.9p | 146.0p |
| Diluted adjusted* | 172.8p | 147.0p |
*Reconciliation to compute the diluted adjusted earnings from operations is as per below:
| £ Millions | 2018 | 2017 |
| Earnings for the purposes of basic and diluted earnings per share | | |
| (profit attributable to equity holders of the Company) | 30.2 | 28.3 |
| Amortisation of intangible assets due to business combination | 2.8 | 0.6 |
| Acquisition costs | 0.6 | 3.3 |
| Non-recurring tax benefits | (0.1) | (3.7) |
| Costs related to ERP implementation | 0.2 | – |
| Adjusted earnings | 33.7 | 28.5 |