Length of Notice - Meetings and resolutions:

S.133(1) provides that any provision of a company's articles shall be void in so far as it provides for the called of a meeting of the such company (other than an adjourned meeting) by a shorter notice than 21 days.  The notice must be in writing. 

S.133(2) provides that, except in so far as the articles of a company make other provision in that behalf (not being a provision avoided by S.133(1), a meeting of the company (other than an adjourned meeting) may be called giving twenty-one days notice in writing.  This in effect means that a company's articles may provide for a longer period of notice than twenty-one days but cannot provide for a shorter period.

By S.133(3) a meeting of a company, if called by a shorter period of notice than that prescribed in S.133(1) or by the company's articles, shall be deemed to have been duly called if it is so agreed -

a)      in the case of the annual simple meeting, through all the members entitled to attend and vote at the meeting; and

b)      and also with in the case of any other meeting, by a majority in number of the members having a right to attend and vote at the meeting, being a majority together holding not less than 95% in nominal value of the shares giving a right to attend and vote at the meeting; or in the case of a company not having a share capital, a majority together representing no less than 95% of the total voting rights at that meeting of all the members.

It was explained in Re: Pearce Duff & Co. Ltd that the mere fact all the members are present at the meeting and pass a particular resolution, either unanimously or by a majority holding 95% of the voting rights, does not imply consent to short notice.  Anyone who voted for the resolution can therefore change his mind afterwards and challenge it.