Part IIIRights in relation to union membership and activities
Time off for trade union duties and activities
171Time limit for proceedings
An industrial tribunal shall not consider a complaint under section 168, 169 or 170 unless it is presented to the tribunal—
a
within three months of the date when the failure occurred, or
b
where the tribunal is satisfied that it was not reasonably practicable for the complaint to be presented within that period, within such further period as the tribunal considers reasonable.