The Apprentice's Nick Hewer has said contestants make mistakes because the environment they're in is "an absolute cauldron".
The 67-year-old, who advises Lord Alan Sugar on the show, also told Newsbeat he didn't think he would do any better if he was a candidate.
"Some of them make the most terrible mistakes, but if I were their age, I would make far more," he said.
"I'm not sure I'd get anywhere even now," he added.
"They're working in an absolute cauldron, in that house, week after week - week, week, week after week!
"They've got one phone call a week, under supervision for about 10 minutes.
"They've got no money, no credit cards, no phones. That's a hell of a place to be in," he said.
Ex-PR man Hewer went on to say that the atmosphere in the house was as if contestants had to fear their rivals "stealing up behind them with a bread-knife".
"I don't blame them for making mistakes.
"Once they're out of the process they return to normal life and they're just like you and me.
He also joked that about how "daunting" candidates found the boardroom face-offs with Lord Sugar
"[You have to] go into that boardroom and be confronted with the black laser eyes that are Lord Sugar's peepers, sweeping like a great big lighthouse across you.
For the first time in the show's history, the 2011 final will feature four candidates, with the winner claiming a £250,000 business investment from Lord Sugar.
This year's finalists are Susan Ma, Helen Louise Milligan, Jim Eastwood and Tom Pellerau.
The Apprentice final will be shown on BBC One on Sunday 17 July at 2100 BST.