Former world super-featherweight champion Alex Arthur admits that it's risky taking on light-welterweight Nigel Wright.

Arthur decided to step up to lightweight after losing his WBO crown to Nicky Cook in September 2008, but a recent blood disorder means he is unable to diet and has forced him to temporarily step up yet another level.

So Arthur will take on friend Wright on the undercard of Amir Khan's world title defence against Dmitriy Salita at the Metro Radio Arena in Newcastle on December 5.

"Of course it's a risk," Arthur said.

"But boxing is all about taking risks. Some people take risks every day in their life. It's what makes great champions.

"I have had problems in the past to get motivated against British fighters.

"But Nigel is a brilliant boxer. He was a great amateur and Nigel is a bigger guy than me.

"That's the challenge, that's the thing that's getting me motivated."

The 31-year-old added: "I always set goals for myself. I want to be the first Scottish boxer to win world titles in three weight divisions.

"If I don't perform on December 5 that dream could be over."

Illness and injury have restricted the Edinburgh boxer to one fight since losing his title, and he took just 93 seconds to stop Mohamed Benbiou in June.

But he dismissed suggestions that he would lack sharpness.

"I have been doing this since I was 10 years old," Arthur said.

"It's like riding a bike, you never forget.

"Ring-rust is an excuse for bad performances. David Haye said this recently, he had been out of the ring for a year and executed a good plan to beat Nikolai Valuev.

"I have been training all year round and had some great sparring in the meantime with the likes of Frankie Gavin and Gary McMillan."

Hartlepool-based Wright includes former British champion Kevin McIntyre among his list of conquests but he admits Arthur poses an unprecedented challenge.

"I have never boxed someone who has been world champion," the 30-year-old said.

"That's a big step for me. I have been in with some great fighters but Alex is an exceptional fighter.

"But the weight could be a factor, I'm a natural light-welterweight."