Thorrington showed no signs of reaction to his hamstring injury which has kept him out injured.
He was involved in the action as early as the first minute when he fired wide.
Town started very strongly with Schofield and Thorrington dangerous down the flanks but the game quickly slowed down to a slower pace in the first half despite close efforts for Andy Booth who nodded a Kenny Irons corner wide.
Excitement was provided in the 11th minute when Howard Forinton was booked for a poorly concealed dive but Town took a deserved lead in the 33rd minute when Thorrington went past two defenders and struck a shot which took a wicked deflection and looped past Mark Tyler.
Town were ahead again but couldn't rest on their laurels as David Farrell, ever-dangerous for the Posh in the closing moments, showed with a couple of close efforts.
Town doubled their lead in the second half when Marc Joseph made a hash of Peterborough's offside trap.
Leon Knight needed no second invitation as he sped into an ideal shooting position and forced a save from Tyler but the ball bounced away and into John Thorrington's path.
The American finished with aplomb and could have had a hat trick moments later but for Tyler and a poor second touch from Andy Booth.
The game was put beyond the visitors when Kenny Irons propelled the ball around the wall and beyond Tyler from a free kick in the 65th minute.
Irons' goal marked the return to McAlpine action of Clyde Wijnhard and the crowd applauded the subsequent departure of John Thorrington.
Peterborough's late consolation, a strike by Andy Clarke who turned Jenkins and put the ball past Margetson and in off the post from the fingertips of the Welshman, was deserved for their efforts but Town were the top team on the day.
Read Mel Booth's Match Report on Thursday - have your say on the match using the form on the right or the messageboard below.
Town (4-4-2): Margetson, Jenkins, Evans, Moses, Gray, Thorrington (Wijnhard 66), Irons (Heary 72), Mattis, Schofield, Knight, Booth (Hay 86)
Subs not used: P. Senior, Macari
Scorers: Thorrington 33, 52; Irons 65
Peterborough (4-4-2): Tyler, Joseph, Rea, Edwards, Farrell, Oldfield, Clarke, Bullard (Fenn 62), Forinton, MacDonald (Williams 68), Tonor (Cullen 68)
Subs not used: Connor, Laurie
Booked: Joseph, Forinton, MacDonald
Referee: Graham Frankland
Attendance: 11,446 (508 away fans)
Match points are on subsequent pages
89 mins: 4 minutes of added time were indicated.
85 mins: Andy Clarke scored a late consolation when he turned past Steve Jenkins from a corner and struck a shot which Margetson could only palm against his post before it bounced over the line.
84 mins: Wijnhard couldn't reach the ball after both he and Mattis had tried to get on the end of the slippery Leon Knight's run towards the Posh area.
82 mins: Schofield turned his man and crossed but his effort missed both Booth and Wijnhard.
81 mins: Farrell tested Margetson but the Welshman was up for it and caught the ball well.
80 mins: The game was effectively safe and Town re-shuffled and opted for patience and a long ball approach.
73 mins: Schofield skewed the ball over the bar with Wijnhard waiting outside the goal.
66 mins: Town were going for goals as Wijnhard joined Booth and Knight slightly wide on the right.
65 mins: Town went 3-0 up with a scorching free kick from Kenny Irons which went round the Posh wall. Clyde Wijnhard was stripped off and ready to come on to join the celebrations. John Thorrington went off to a round of applause.
62 mins: Thorrington was sent flying by MacDonald with a very dangerous tackle.
60 mins: Thorrington's cross was too high for Leon Knight.
58 mins: Thorrington had his shot parried - he was looking for his hat-trick. Andy Booth recovered the rebound but lost his balance with Knight and Thorrington waiting.
52 mins: Leon Kight broke free of the very poor Posh offside trap (courtesy of Marc Joseph) and dashed into a shooting position before unleashing a shot which Tyler palmed away into the path of the waiting John Thorrington who poked home for his and Town's second!
51 mins: The game was finely balanced in the chill McAlpine wind. Town were playing on for more.
A mainly quiet match saw John Thorrington get back in amongst the action after just 40 seconds with an early effort which went wide.
The Terriers had started well but the game quickly petered out into a dull affair before Thorrington, back from injury, hit a deflected shot past Mark Tyler for 1-0.
Peterborough had a couple of chances to equalise through David Farrell late on and the referee had earlier booked Howard Forinton for a blatant dive in Martyn Margetson's area.
43 mins: Moses and Booth combined to clear off the line after Margetson had flapped against a Joseph header. Posh were always dangerous with the scores so delicately placed.
41 mins: Knight chased down a prospect but Tyler was there to clear hurriedly.
39 mins: Andy Edwards needed treatment and play was stopped in a threatening position but Bullard swept his effort wide to jeers from the Kilner Bank.
37 mins: John Thorrington's pass for Leon Knight sold him short.
34 mins: Farrell's shot was wide.
33 mins: John Thorrington celebrated his return to the Town side by skipping past two defenders with Leon Knight in support and blasting in a shot which took a wicked deflection and looped past Tyler to open the scoring!
32 mins: Farrell's poor cross was a waste after he had beaten Steve Jenkins.
29 mins: Thorrington teased his way into a good crossing position and pinged in an intelligent cross which was intercepted and cleared.
27 mins: Schofield hit the ball into the ground, making it easy for Tyler, after Knight's pass.
21 mins: Irons' corner was put in with pace and Andy Booth somehow misdirected his header just wide!
20 mins: Schofield's cross found Thorrington who won a corner.
17 mins: Booth clattered Rea as the game became scrappy.
14 mins: Irons' corner was missed by Jenkins and Posh cleared.
13 mins: Evans' long ball was too long for Knight and Schofield who were blown offside.
11 mins: Howard Forinton was booked for blatantly diving in the Town penalty area. He was booked for his theatrics.
11 mins: Forinton didn't challenge Margetson with a poor shot.
9 mins: Thorrington laid it off to Mattis who ran upfield to test Margetson
6 mins: Schofield was beaten by Tonor as Peterborough weathered the early Town attacks.
3 mins: Danny Schofield's shot was deflected away after Steve Jenkins' quick throw eventually fell to the youngster via Andy Booth.
1 min: John Thorrington hit an early effort which went wide.
John Thorrington returned to the starting lineup to replace the unlucky Simon Baldry who was injured in the 3-3 draw against Colchester.