The Hoops boss was raging after conceding an injury-time equaliser to Dundee United last week and watched in disbelief again as they passed up on the chance to leapfrog rivals Rangers at the top of the table after being two goals clear against Inverness and seemingly cruising.

Ki Sung-yueng had given the home side the interval lead before substitute Paddy McCourt, on early for injured skipper Shaun Maloney, scored a wonderful solo second in the 65th minute.

However, a lapse by Hoops' defenders Daniel Majstorovic and Thomas Rogne five minutes later allowed Richie Foran to reduce the deficit before Grant Munro levelled from close range to keep Celtic two points behind Rangers who have a game in hand.

"It was worse than deja vu," Lennon said. "I am absolutely livid. It's not the goals, it's the manner of the goals we lost from a very strong position.

"We were two nil up and looking comfortable. It's a bit of complacency, slackness, lack of concentration and it's not good enough.

"You can't afford to do that at any level, never mind this level.

"The first goal is slapstick defending.

"It's two centre halves who are pretty consistent but who just give a simple goal away without the opposition having to work for it.

"That goal deflated the team and players have to hold their hands up and take responsibility sometimes.

"The goals we are giving away at the moment is calamitous and we have to deal with that very quickly.

"It's starting to creep in and it's something that we have to eradicate very quickly.

"We are obviously not getting the message through."

Much of the attention was focused on referee Alain Hamer and his officials who flew in from Luxembourg to take charge of the game after grade Scotland's grade one officials called a strike as a protest about increasing criticism, much of which had come from the Parkhead club.

Hoops striker Daryl Murphy had the ball in the net in the first half only to be ruled offside but Lennon had no complaints.

He said: "I haven't seen the incident again but I can't point the finger at that for the reason why we dropped points today.

"The referee did fine, I have no qualms with him.

"We were poor through the spine of the team, particularly in the second half.

"I should be sitting here talking about Paddy McCourt but I'm not and if anyone should be upset it's Paddy."

McCourt agreed with Lennon's assessment that there is a mental toughness missing from the squad.

"I am not even thinking about my goal, I am just disappointed about the two points dropped," the Irishman said.

"You would have thought we would have learned our lesson from last week but obviously not so there was a very dejected dressing room.

"It would be silly to say that there wasn't a lack of mental toughness when all the evidence is pointing towards that.

"Instead of getting the ball down and passing it we did seem to panic and I include myself in that and it did get scrappy.

"It's something that we will have to rectify over the coming weeks."

Caley boss Terry Butcher, whose side have now gone a year unbeaten on the road in the league, revealed the struggle to get through the snow and down from the Highlands.

"It's 52 weeks now, we will try to make it through to the end of 2010," the former Rangers defender said.

"But we had the journey from hell today. I live up in the hills now and left the house at 7am when there was a foot of snow.

"I was coming down the hill to Loch Ness and it was scary. We left Inverness at 8.30am and got here just at 2pm when the team sheets had to be in.

"We rushed to get to the pre-match meal, rushed to get here, rushed to get on to the pitch, so no wonder we didn't play well in the first half.

"But the players don't moan, they are no histrionics, no Billy-big timers, there is a real good spirit.

"The players get the duvets, the pillows and get on the bus, they just get on with it.

"There's a lot of mutual respect between the lads, they are a strong unit.

"There is a lot of belief about us and it showed."

On Hamer's performance, Butcher said: "I wanted the referee to be anonymous and he was.

"I hope that the headlines are about our performance and the game which it should be.

"If the referee is anonymous, then he has had a great game."