The 39-year-old joined the Scottish Premier League side in November 2011, replacing Derek McInnes following his move to then-Championship outfit Bristol City.

Lomas has now made a similar switch, succeeding Kenny Jackett at the helm after the Englishman elected to end his near six-year association with the club.

Former West Ham midfielder Lomas led St Johnstone to finishes of sixth and third in his two seasons in charge in Scotland - the latter achievement marking the Perth club's highest-ever placing in the Scottish Premier League and handing them a European place.

Millwall chairman John Berylson was understandably delighted to announce the news, with the paperwork now expected to be completed after Lomas returns from holiday next week.

"I was tremendously impressed with Steve," Berylson told the club's official website. "He has great passion and energy, knows a lot about Millwall as a club already, and this is a job he is genuinely hungry for.

"In some respects, following Kenny Jackett is a tall order, but Steve is very different from his predecessor, younger and with a fresh approach. 

"I believe our fans will take to him, and to those who say we shouldn't have appointed a former captain of our biggest rivals (West Ham), my response is, he has the desire to become a great Millwall manager. 

"He understands the rivalry and is keen to be judged over time on his commitment to our club and what he can help us achieve. 
"From our point of view, we want the best man for the job, and we believe that man is Steve Lomas. 

"I would like to thank the chairman of St Johnstone for allowing us to appoint Steve and for the courteous and professional way in which our business has been conducted."