Schumacher also praised Smith’s scouse accent – saying it was better than his own.
“I was checking with Sheridan if mine was OK, because it’s just brilliant,” he said.
Schumacher said he had not originally envisaged Socha, who was previously in This is England, as playing Matty, but on the first day of filming, he “totally nailed it”.
“He blew it out of the water,” he added.
He said Socha and Smith – from the very first read-through – had “magic” chemistry, for the “funny and dark” drama.
Director Al Mackay also said the pair “sparked off each other”.
While most of the filming was done in the Liverpool area, some scenes were filmed in Bolton and Tockholes in Darwen, Lancashire.
The Royal Arms pub in Tockholes had the cast and crew using their facilities when filming took place nearby last year.
Emma Ball, who has been running the pub for nearly three years, said it was lovely to host them.
“It was lovely to have them in the pub.
“We are only a tiny village – and are really excited to watch the Cage and see Tockholes on it.”