7 Earnings per share

2016
£m
2015
£m
Profit after tax attributable to equity holders of the company397.5271.2
2016
pence
2015
pence
Earnings per share
Basic58.339.8
Diluted58.239.7

Basic earnings per share is calculated by dividing profit after tax for the financial year attributable to equity holders of the company by 681.9 million, being the weighted average number of shares in issue during the year (2015: 681.9 million). Diluted earnings per share is calculated by dividing profit after tax for the financial year attributable to equity holders of the company by 683.0 million, being the weighted average number of shares in issue during the year including dilutive shares (2015: 683.3 million).

The difference between the weighted average number of shares used in the basic and the diluted earnings per share calculations represents those ordinary shares deemed to have been issued for no consideration on the conversion of all potential dilutive ordinary shares in accordance with IAS 33 'Earnings per Share'. Potential dilutive ordinary shares comprise outstanding share options awarded to directors and certain employees (see note 2).

The weighted average number of shares can be reconciled to the weighted average number of shares including dilutive shares as follows:

2016
million
2015
million
Average number of ordinary shares – basic681.9681.9
Effect of potential dilutive ordinary shares – share options1.11.4
Average number of ordinary shares – diluted683.0683.3