The young goalkeeper has moved to QPR from Wycombe Wanderers, and he is expected to compete with Alex Smithies for a place in between the sticks at Loftus Road.
Allen believes that Ingram could have the potential to play at the top level, and he is surprised that QPR snapped him up ahead of Premier League clubs.
"Queens Park Rangers have picked up one of the best signings of the window in Matt Ingram," Allen said.
"I cannot believe no-one from the Premier League took the goalkeeper from Wycombe, who also happen to be in League Two."
Ingram is just 22, but he has a vast amount of Football League experience, having been Wycombe’s first choice stopper for the past few seasons.
He has impressed in Gareth Ainsworth’s side, and his arrival at QPR signifies a change in their transfer strategy.
Jimmy Floyd Hasselbaink has already stated a desire to create a young, British core to his side - and his additions so far, suggest that he will target players from the lower leagues.
QPR have signed Ingram and Conor Washington, who was formerly of Peterborough United, so far in January, as they move away from the policy which has seen them assemble an ageing squad at Loftus Road.