Basic profit/(loss) per share is calculated by dividing the profit/(loss) 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 which are accounted for as treasury shares.

Diluted profit/(loss) 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 categories of potentially dilutive shares, namely share options and shares held pursuant to the JSOS.

For the year ended 1 December 2013 there was no difference in the weighted average number of shares used for the calculation of basic and diluted profit/(loss) per share as the effect of all potentially dilutive shares outstanding was anti-dilutive.

Basic and diluted profit/(loss) per share has been calculated as follows:

 52 weeks
ended
30 November
2014
Number of
shares
(m)
52 weeks
ended
1 December
2013
Number of
shares
(m)
Issued shares at the beginning of the period, excluding treasury shares582.5578.3
Effect of share options exercised in the period2.11.4
Effect of treasury shares disposed of in the period0.30.3
Effect of shares issued in the period
Weighted average number of shares at the end of the period for basic earnings per share584.9580.0
Potentially dilutive share options and shares29.4
Weighted average number of diluted ordinary shares614.3580.0
£m£m
Profit/(loss) attributable to the owners of the Company7.3(12.5)
 pencepence
Basic profit/(loss) per share1.24(2.16)
Diluted profit/(loss) per share1.18(2.16)

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 80,441 share options under the company ESOS scheme, 10,163 share options under the SAYE2 scheme, 46 under the SAYE3 scheme and the issue of 22,443 Partnership Shares under the SIP.