The striker scored from the penalty spot in the 79th minute before the Canaries levelled two minutes later through Kieran Dowell. But Collins had the final say, adding his second of the game with seven minutes remaining and then his hat-trick in additional time.

Manager Nathan Jones handed a first start to new signing Rhys Norrington-Davies, whilst James Shea started between the sticks in place of Simon Sluga, who is away on international duty with Croatia. Matty Pearson also returned to the starting line-up as the gaffer made three changes from the last competitive match against Blackburn Rovers.

Elliot Lee came close to give the Hatters an early lead but after Sonny Bradley nodded the ball into his path from Luke Berry’s corner, Lee sliced his shot just wide of the target.

Norwich’s best chances of the half fell to Lukas Rupp, who twice tried his luck from distance, one narrowly wide and one which Shea was quick to gather at the second attempt just before Jordan Hugill could gobble up the rebound.

On the stroke of half-time, Martin Cranie played a well-timed ball through to Collins, but the striker uncharacteristically fluffed his lines and missed the target.

Shea was called into action in the second half when Alexander Tettey struck a fierce effort towards goal which he done well to tip around the post. From the resulting corner, the goalkeeper got low quickly to palm away Marco Stiepermann’s attempt and the danger was cleared.

Shortly after new signing Jordan Clark entered the fray, he produced a dangerous cross into the box which fell to Pelly-Ruddock Mpanzu, who was brought down for a penalty kick by Mario Vrancic. Collins stepped up and calmly slotted the ball home to give Town the lead with just over 10 minutes remaining.

Then ensued a crazy period, in which time Dowell fired in an equaliser for Norwich and just two minutes after the Hatters took the lead once more – again through Collins.

It was Clark again with the initial cross, Mpanzu brought it down and via a slight deflection, the 29-year-old fired into the bottom corner.

Collins completed his hat-trick in added time at the end after Clark squared the ball to him and he finished calmly to book Town's place in the next round of the cup, ahead of the Championship opener next Saturday against Barnsley.

Town: Shea, Cranie, Bradley (C), Pearson, Norrington-Davies; Rea, Mpanzu, Berry, Lee (LuaLua 85); Cornick (Clark 72), Collins.

Subs not used: Isted, Hylton, Shinnie, Moncur, Bree.

Goals: Collins (79,83, 90+5)

Yellows: Rea

Norwich: Barden, Mumba, Zimmermann, Klose (Vrancic 59), McCallum (Sitti 85); Rupp Tettey, Stiepermann, Dowell, Martin (Hernandez 72); Hugill.

Subs not used: McCrackin, Sitti, McAlear, Omobamidele, Hondermarck.

Goals: Dowell (81)

Yellows: McCallum

Referee: John Busby