Basic earnings per share are calculated by dividing the profit attributable to ordinary shareholders by the weighted average number of ordinary shares in issue during the period. The weighted average number of shares excludes shares held by an Employee Benefit Trust (see Note 23) and has been adjusted for the issue/purchase of shares during the period.

For diluted earnings per share, the weighted average number of ordinary shares in issue is adjusted to assume conversion of all dilutive potential ordinary shares. These represent share options granted to employees where the exercise price is less than the average market price of the Company's ordinary shares during the 53 weeks to 3 April 2020.

The Group has also chosen to present an alternative earnings per share measure, underlying earnings per share, with profit adjusted for non-underlying items because it better reflects the Group's underlying performance. This measure is defined in the Glossary.

For the period53 weeks to
3 April
2020
Number of
shares
m*
52 weeks to
29 March
2019
Number of
shares
m
Weighted average number of shares in issue199.1199.1
Less: shares held by the Employee Benefit Trust (weighted average)(2.1)(2.0)
Weighted average number of shares for calculating basic earnings per share197.0197.1
Weighted average number of dilutive shares3.32.1
Weighted average number of shares for calculating diluted earnings per share200.3199.2
For the period53 weeks to
3 April
2020
£m
53 weeks to
3 April
2020
(pre-IFRS 16)
£m*
52 weeks to
29 March
2019
£m
Basic earnings attributable to equity shareholders17.517.641.9
Non-underlying items (see Note 5):
Operating expenses34.232.17.8
Finance costs-
Tax on non-underlying items(5.0)(4.7)(1.4)
Underlying earnings before non-underlying items46.745.048.3

* Note that all numbers are quoted as per IAS 17 in order to show comparability with the prior period.

Earnings per share is calculated as follows:

For the period53 weeks to
3 April
2020
53 weeks to
3 April
(pre-IFRS 16)
2020
52 weeks to
29 March
2019
Basic earnings per ordinary share8.9p8.9p21.2p
Diluted earnings per ordinary share8.7p8.8p21.0p
  
Basic underlying earnings per ordinary share23.7p22.9p24.5p
Diluted underlying earnings per ordinary share23.3p22.5p24.2p