The former Liverpool and England midfielder launched a blistering attack on the Arsenal defence especially over the lack of organistion as Craig Dawson scored twice with easy headers in each half.
Arsenal have lost their last three league matches 3-1 away from home. They trail fourth-placed Liverpool by five points having played one game less.
Since the 3-1 defeat at Chelsea in early February, Arsenal have suffered two 5-1 defeats to Bayern Munich in the Champions League last 16 and league losses at Liverpool and West Brom.
"I have never seen such shambolic defending..the players have let Arsene Wenger down and Arsenal down today," said Redknapp.
"That’s the worst Arsenal performance I’ve seen in a long, long time.
"That's the sort of performance that gets managers the sack.
Read the full article on eurosport.co.uk: Redknapp slams 'shambolic and diabolical' Arsenal in West Brom defeat