Brown, who was a boyhood Sunderland supporter, has been installed as a contender to take over at the Stadium of Light after Roy Keane's resignation on Thursday.

Tigers boss Brown moved quickly to play down the rumours by telling Sky Sports News that he is focused on his job at the KC Stadium.

And City chairman Duffen, who has Brown under contract until 2011, is also confident that the 49-year-old will not be returning to the North-East.

Duffen understands why Brown has been mooted as a candidate for the Black Cats' vacancy, but says he is committed to the task of turning City into a big club.

"I don't think there's any club that Phil would leave Hull City to manage at this moment in time," Duffen told the Hull Daily Mail.

"If people are linking Phil with Sunderland, it shows how little they understand about what's going on at Hull City. He's started on a journey where he is fulfilling dreams.

"He's got the chance in front of him that very few people have and that is to create a big football club.

"The speculation is inevitable because he comes from the North East of England and we're sixth in the Premier League. It's one of those things."

Duffen later added: "He is contracted to the club for three years and he is in the middle of a project that has just begun.

"It is a great adventure, a journey that he is enjoying and he has got an opportunity most managers never have to build a big football club.

"We're actually rather disappointed he was only third or fourth favourite for the Sunderland job because that certainly underestimates his abilities!

"He is a fantastic guy, a great manager and he is very busy doing what he is doing and enjoying it."

Hull produced an outstanding finish to their last campaign to secure promotion via the Championship play-offs.

The club have not looked back since with Brown making 12 summer signings and lifting the club into sixth place ahead of Saturday's visit of Middlesbrough to the KC Stadium.

Duffen said: "We are coming towards the end of the calendar year now, which obviously eclipses two seasons.

"If you look back at what has been achieved in that 12-month period it is absolutely outstanding and I doubt any football club has achieved so much in one 12-month period.

"Phil has done an incredible job and he is very much in the early days of something that he is enjoying and I am very happy to be on that journey with him.

"I am absolutely convinced it is a project he is looking to complete whilst at Hull City."