By Edward Chaykovsky

IBF welterweight champion Kell Brook (36-1, 25 KOs) is full steam ahead to a mandatory showdown with unbeaten Olympian Errol Spence (21-0, 18 KOs).

The two sides are very close to finalizing a deal with a purse bid scheduled to take place on Tuesday. Their negotiations heated up after Brook was unable to reach a deal with his domestic rival Amir Khan (31-4, 19 KOs), who stood firm on several of the fine points - specifically a deal-breaking 70-30 split of money.

There were some questions as to whether or not Brook would squeeze back down to the welterweight limit of 147-pounds.

The last time Brook saw action was in September, when he jumped up two weight divisions to suffer a stoppage loss at the hands of middleweight king Gennady Golovkin at the O2 Arena in London.

Brook's own team members, which includes promoter Eddie Hearn, were advising him to vacate the title and move up the junior middleweight limit of 154. They believe that he'll be a better fighter and stronger fighter at the weight. There is some concern that Brook may deplete his body in making 147 for Spence.

Brook is refusing to give up the belt.

"All that work just to give it up? Never ducked a challenge in my life. Here to give the fans what they want. Errol Spencer you are next," Brook stated.

Spence has been waiting in the wings since winning last year's final eliminator with a knockout of Italian Olympian Leonard Bundu.

If they head to the purse bid, there is a 75-25 split in Brook's favor. Purse bid or not, Spence will have to pack his luggage because the fight is certain to take place on UK soil.

Hearn is looking at date in late May, with Brook's hometown of Sheffield being the current frontrunner to host the contest.