UK Athletics' new performance director Neil Black is nicknamed "The Wolf" by athletes after the fixer in the film Pulp Fiction - and he claims he is even tougher than Charles van Commenee, the infamously tough outgoing head coach.

Black, a former physio who became UK Athletics head of sports science, said he had a different approach to van Commenee who was viewed as "a monster" by some athletes but he had even less tolerance for failure.

He said: "I'm harder in the sense that I will push even further than he did. I want change more quickly. I'm less tolerant but I feel less frustrated at going at a slower rate. The hardness just comes from confidence and clarity and being sure about what you need to do."

Black added: "Charles would go and say you're underperforming and that's great for some and absolutely terrible for others. Some people love him for his directness and some people think he's a monster. I'll go and say, 'Tell me about your performance', it will take a little bit longer but the end result is the same - they work out their performance isn't good enough."

Former heptathlete Kelly Sotherton labelled him on Twitter as "harder than a conker soaked in vinegar" and he does not dispute the description.

"Kelly will really relate to the fact I've had to give her some tough information," added Black, who is originally from Northumberland but now lives in Shropshire.

"'Your tissue is snapped, your competition is over, your career is over', I've had to give her that hard information. I've started with her saying, 'I'm going to tell you the truth, you're going to cry, you're going to recover in a couple of hours and say what are we going to do now'. That's the process we went through with Kelly."

Britain's Olympic long-jump champion Greg Rutherford gave Black his nickname - after the character in the film who is called in to clean up the mess and dispose of a dead body.

Black admitted he quite enjoyed the tag: "There is a guy in Pulp Fiction called The Wolf who is the fixer, and in the film he's the guy who gets rid of the dead bodies. It's not a brilliant analogy but it is a little bit of what people perceive.

"Greg Rutherford gave it to me. I've seen the film a long time ago. I quite like it in a way because it does describe part of how I work, but without clearing the dead bodies. But I am good at clearing up mess. Sometimes someone just has to say, fine I'll do it, and let's get it sorted and then address the cause of the mess."