Basic profit per share is calculated by dividing the profit attributable to equity holders of the Company by the weighted average number of ordinary shares in issue during the period, excluding ordinary shares held pursuant to the Group's JSOS on an allocated basis which are accounted for as treasury shares.

Diluted profit per share is calculated by adjusting the weighted average number of ordinary shares outstanding to assume conversion or vesting of all dilutive potential shares. The Company has two (2014: two) classes of instruments that are potentially dilutive, namely share options and shares held pursuant to the JSOS.

Basic and diluted profit per share has been calculated as follows:

 52 Weeks
Ended
29 November
2015
Number of Shares (m)
52 Weeks
Ended
30 November
2014
Number of Shares (m)
Issued shares at the beginning of the period, excluding treasury shares586.1582.5
Effect of share options exercised in the period2.22.1
Effect of treasury shares disposed of in the period0.3
Effect of shares issued in the period
Weighted average number of shares at the end of the period for basic earnings per share588.3584.9
Potentially dilutive share options and shares31.129.4
Weighted average number of diluted ordinary shares619.4614.3
 £m£m
Profit attributable to the owners of the Company11.87.3
 pencepence
Basic profit per share 2.011.24
Diluted profit per share1.911.18

The only transactions involving ordinary shares or potential ordinary shares between the reporting date and the date of these financial statements were the exercise of 16,754 share options under the company ESOS scheme, 2,903 share options under the SAYE3 scheme and the issue of 28,463 Partnership Shares under the SIP.