In from cold, forgotten man Neil Lennon is back on centre stage

Rangers led Celtic by six points and had a game in hand when Lennon joined Gordon Strachan's coaching staff on 3 April, 2008. His first game in the dugout saw Celtic lose to Motherwell but they then went on a run of seven consecutive victories to wrest control back from Rangers and secure a third successive league championship for Strachan.

Much of the credit went to Lennon for his ability to gee up a dressing room which had gone quiet in the face of Rangers' apparent dominance. No shrinking violet, the former midfielder brought all his experience to bear, instilling a fighting spirit and letting the players know what it meant to play for the club.

However, there is another side to Lennon, one he spoke of candidly in his autobiography and again last year in a BBC TV programme about depression in sport. Lennon talked of his ten-year battle with the illness which left him an "emotionless" wreck.

"I was vacant in terms of my feelings. I was never euphoric, never angry. I couldn't cry," he explained. "I was waking up on the hour, every hour, and the bed would be soaking with sweat and I'd just be thinking to myself, 'What's wrong?'"

The illness runs in his family and he admitted he feared he would never fully escape it.

"I have three sisters and my mother and aunts and uncles who have suffered from it. Until you experience it you can't really explain to others how difficult it is.

"You have tunnel vision, a shadow surrounding you. You're not thinking straight. Being depressed is one thing, having depression is another. Depression is an illness.

"When Stan Collymore said he had it the reaction with a lot of players and even myself was, 'What's he got to be depressed about?' But it's more than that. It's a common illness, common among young men, regardless of what they do in life.

"If you tell people you have depression they just say, 'Get a grip', and that's the worst thing they can say. You feel as if you are the only person who has this and the more you talk to people you realise you're not.

"I have been in a room full of people and felt like the loneliest guy in the world. The only thing I wanted to do was lie in bed and shut myself away."

Lennon, who takes charge at Celtic from today, now takes medication to deal with the illness. He will be assisted in running the first team by Johan Mjallby.

While it's fanciful to suggest Celtic could overhaul Rangers this season – the lead this time around is ten points and the Ibrox side have two games in hand – there is still the Scottish Cup to play for and Lennon has some unfinished business on that score.

His last game as a Celtic player was the 2007 Scottish Cup final against Dunfermline when he was hauled off during the second-half and replaced by Gary Caldwell with the game goalless. A clearly agitated Lennon signalled his displeasure but Celtic went on to win the game.

The cup is their last chance to salvage something from a dismal season and, if anything, the curious set of midweek results will likely aid their chances of success. The elimination of Hibs and Rangers from the competition means Celtic have been instilled as odds-on favourites and now face Ross County in the semi-final at Hampden next month.

His appointment, albeit on a temporary basis, represents a remarkable turnaround for Lennon who had found his role at the club reduced under Tony Mowbray, who brought in his own assistants in Mark Venus and Peter Grant.

Lennon was less visible on the first-team training ground and was deployed often in a scouting role. The scrapping of the reserve league further diluted his duties and his title before yesterday was "Coach of the Development Squad". Out of sight and as a result, out of mind, he had become the forgotten man of the coaching set-up at Parkhead.

A former club captain, he had spent seven years anchoring the Celtic midfield but left at the end of the 2006-07 season for short spells with Nottingham Forest and Wycombe Wanderers. His time in the English lower divisions was not particularly happy and when the Parkhead club came calling again in April 2008 he jumped at the chance to return in a coaching capacity under Strachan.

One of Strachan's coaching lieutenants, Tommy Burns, was battling with cancer at the time, a fight he would lose. The arrival of Lennon helped ease the strain on Strachan and gave a Celtic a fresh impetus. "He had a big influence," Paul Hartley said after the title had been won in 2008. "He's been fantastic for me, for the team. He knows what it's about here and knows how to win a championship."

Later that year, Lennon was viciously attacked in a Glasgow street by two Rangers fans after the Ibrox side had won an Old Firm match, and he gave evidence in a prosecution case which saw his attackers jailed for two years.

Since then, he has remained out of the media spotlight, but he will be back in the full glare of attention today as he takes up his new duties, including a pre-match press conference, ahead of tomorrow's SPL match with Kilmarnock.

The title is gone this season but Celtic's directors are gambling on Lennon bringing back the winning mentality, in the short term at least.

CELTIC ROLL CALL OF MANAGERS

WILLIE MALEY (1888-1940)

Honours: 16 League titles, 14 Scottish Cups, Glasgow Exhibition Trophy (1902), Empire Exhibition Trophy (1938).

JIMMY McSTAY (1940-45)

Honours: none (no official league during Second World War).

JIMMY McGRORY (1945-65)

Honours: 1 League title, 2 Scottish Cups, 2 League Cups, St. Mungo Cup (1951), Coronation Cup (1953).

JOCK STEIN (1965-78)

Honours: 10 League titles, 8 Scottish Cups, 6 League Cups, 1 European Cup (1967).

BILLY McNEILL (1978-83)

Honours: 3 League titles, 2 Scottish Cups, 1 League Cup.

DAVIE HAY (1983-87)

Honours: 1 League title, 1 Scottish Cup.

BILLY McNEILL (87-91)

Honours: 1 League title, 1 Scottish Cup.

LIAM BRADY (91-93)

Honours: none.

LOU MACARI (1993-94)

Honours: none.

TOMMY BURNS (1994-97)

Honours: 1 Scottish Cup.

WIM JANSEN (1997-98)

Honours: 1 League title, 1 League Cup.

JOZEF VENGLOS (1998-99)

Honours: none.

JOHN BARNES (1999-2000)

Honours: none.

* KENNY DALGLISH (2000)

Honours: League Cup.

MARTIN O'NEILL (2000-2005)

Honours: 3 League titles, 1 League Cup, 3 Scottish Cups.

GORDON STRACHAN (2005-2009)

Honours: 2 League titles, 1 League Cup, 1 Scottish Cup

TONY MOWBRAY (2009-2010)

Honours: none

* Denotes interim manager