These excerpts taken from the BP 6-K filed May 22, 2008.
Length of notice
58 A general meeting of the Company shall be called by notice of at least such length as is required in the circumstances by the Statutes. The Company may give such notice by any means or combination of means permitted by law. Notwithstanding that it has been called by a shorter notice than that specified above a general meeting of the Company shall be deemed to have been duly called if it is so agreed:
(i) in the case of an annual general meeting by all the members entitled to attend and vote thereat; and
(ii) in the case of an extraordinary general meeting by a majority in number of the members having a right to attend and vote thereat, being a majority together holding not less than 95 per cent. in nominal value of the shares giving a right to attend and vote at the meeting (excluding any shares in the Company held as treasury shares).
To the fullest extent permitted by law, the accidental omission to give notice to or the non-receipt of notice by any person entitled thereto shall not invalidate the proceedings at any general meeting.