Wade, pictured, is set to take charge for the last time on Saturday at Corby Town before stepping aside after resigning on Thursday with the club just a point behind current leaders Buxton.
Originally appointed as the club's caretaker boss in March 2013 as the successor to Paddy Atkinson, Wade narrowly missed out on guiding the Spartans to promotion in May as EVO-STIK NPL Premier Division runners-up.
Armstrong, who had agreed a one year contract at Croft Park with an option on another, enjoyed a long playing career at Newcastle United, Stockport County, Middlesbrough and Ipswich Town before spells at Bradford City, Doncaster Rovers and Darlington.
Now 41, he also played and scored for Stockport in Blyth’s FA Cup tie there in 1997. At Ipswich he scored the winner in a 1-0 victory over Italian giants Inter Milan in the UEFA Cup during the 2001-02 season.
Blyth Spartans chairman Tony Platten said: “It is usual for managers to leave clubs when there are problems on the pitch, in terms of results. However, here at Blyth, we do it in a different way. Tom was very happy with the way things were working out on the pitch, but felt he had taken the club as far as he could and that - under the circumstances - a change was required. A unique opportunity then arose to bring to the club a new person with fresh ideas and drive and he jumped at the chance.
“After several unbelievably successful seasons at the club, including reaching the third round of the FA Cup, winning the Senior Cup and then being top of the league for the vast majority of last season - only to cruelly miss out on promotion - it would be normal for a manager to bask in the glory. Not Tom though, who has steered us to the top end of the league table already this time round.
“Tom, who was born and bred in Blyth and has always put the club first, identified the possibility of taking the club to a new level by bringing in the highly regarded Alun Armstrong. After discussions, Alun decided that he wanted his future in football to be in club management and quickly decided to resign from his job at Middlesbrough FC to take over the management role of possibly the most famous Non-League club in the world.”
Armstrong is now looking forward to taking charge for the first time next Tuesday night when Spartans host Spennymoor Town at Croft Park in the EVO-STIK NPL's top flight.
He said: “I can’t wait to get started. It’s a very exciting challenge for me and my main aim is to win promotion - after we so narrowly missed out on it last season. I’m used to challenges, from becoming a professional footballer to now running my own business and coaching at Middlesbrough. Becoming manager at a club like Blyth Spartans is something really special.”
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