Lifelong Celtic supporter Lennon announced he would leave on his own terms at the end of the season, and will sign off after the Tennent's Scottish Cup final against Dunfermline on May 26.

He said: "It will be a real wrench to leave, but I have thought long and hard about this decision and believe that it is the right one.

"I feel it is right to go out on a high and given that we have just secured the league title for the second year running, I believe that this is the best decision at the best time."

Lennon is likely to return to the English game which he left in December 2000 when, with his old boss Martin O'Neill beckoning, he moved from Leicester to Celtic for £5.75million.

Considering they paid £4.8million for Brazilian misfit Raphael Scheidt earlier that year, Celtic compensated when they invested in Lennon.

To replace him could be costly, but Strachan does not expect to find a ready-made substitute for the man he made captain after replacing O'Neill in 2005.

In youngster Evander Sno he may have a long-term replacement; in Thomas Gravesen and Paul Hartley he may have two immediate contenders for the role, although the deep-lying midfield role would mean both having to rein in their attacking instincts.

"Neil has been a tremendous asset to Celtic and a great help to me since I came to the club," manager Strachan said.

"He is a true competitor and has always been a good team-mate, which I'm sure every player here now, or who has played alongside him in the past would confirm."

Lennon has helped Celtic win five league titles and the Scottish Cup on three occasions, and if Celtic will miss him, Rangers will surely be glad to see the back of the man who has been integral to the success of their Old Firm rivals.

The 35-year-old had been expected to open negotiations over a new contract, and it remains unclear how far those talks went, or if they ever started.

Celtic were adamant the decision to leave was all Lennon's.

Chief executive Peter Lawwell said: "Clearly, we are all disappointed to see Neil leave the club, but it is important that we celebrate Neil's contribution and all that he did in bringing such success to the club in recent years.

"Rightly, since he joined the club, Neil has been a firm favourite with our supporters and I know that, as captain, he has enjoyed greatly winning back-to-back championships for the club and its supporters.

"On behalf of the Celtic board I would like to sincerely thank Neil for his magnificent contribution to the Club. Everyone at Celtic wishes Neil the very best for the future."

Lennon could find offers come in from abroad, with Mo Johnston at Toronto FC reported to be interested in a deal, and a job in management could also tempt him.

He will consider those options after the cup final, and is planning on making his final month as a Celtic player as successful as possible.

"I have enjoyed my time at the club immensely," said the former Northern Ireland midfielder.

"I have worked with two fantastic managers in Gordon Strachan and Martin O'Neill, enjoyed working with some quality players and had a great relationship with the Celtic board and all the staff at the club.

"I would also like to thank the Celtic fans for their support. I have enjoyed a good relationship with supporters and sincerely appreciate the backing which they have given me over a number of years.

"This season has been particularly pleasing, having won the championship, making the Scottish Cup final and obviously getting to the last 16 in the Champions League.

"It was a boyhood dream to play for the club I loved - I am very proud to have achieved this and played for Celtic for so many years and clearly, when Gordon Strachan made me captain of the club I was, of course, extremely honoured.

"I look forward to joining my team-mates and the manager in lifting the SPL trophy on Sunday. Great credit should go to the manager and his staff for all they have done over the past two years.

"We still have a good bit to do before the end of the season and I will be doing all I can to make sure we bring the Scottish Cup back to Celtic Park."

Lennon has provided the protective shield in midfield during the era of sustained success, the like of which Celtic had not known since the early 1970s.

He made his 300th appearance for Celtic in the 2-1 win at Kilmarnock on Sunday which clinched a second successive league title.

Strachan expects to miss Lennon's influence, on and off the pitch.

"We fully respect his decision and I understand fully that he feels the end of the season is the right time to leave the club," said Strachan.

"Neil is proud of his achievements at the club, and rightly so, and very proud to be captain of Celtic. He has been vital to our success, winning two league championships in a row and the CIS Cup, as well as reaching this season's Scottish Cup final.

"And to captain Celtic as the club reached the last 16 of the Champions League for the first time was also a tremendous achievement.

"I would like to thank Neil, on a personal level for being a great captain and indeed a friend, through some difficult moments.

"On behalf of all the coaches and backroom staff here I would also like to thank him for everything he's done for Celtic, and we wish him every success for the future."