Where a business intends to make 20 or more staff redundant in a 90 day period, the law stipulates that a minimum period of consultation with unions or staff representatives must take place.
In cases where between 20 and 99 staff are being dismissed, the minimum consultation period is 30 days. In the case of large scale redundancies of 100 or more staff, this minimum period is set to be cut from its current 90 days to 45 days. The change will come into force in April 2013.
Note that while there is no statutory minimum consultation period where fewer than 20 staff are going, employers must nonetheless follow a fair process and consult adequately with relevant employees regardless of the overall numbers being dismissed.