Dereham's title challenge has received a blow after they were ordered to replay their game against Diss having fielded an ineligible player in the original fixture.

The Magpies won the match, on February 2, 2-0, but Scott Roberts – who came on as a substitute – should have been suspended after being sent off in a reserve game at Brightlingsea on January 12.

The Thurlow Nunn League have ordered that the game be expunged from the records and replayed on Saturday, May 4.

Dereham's general secretary, Ray Bayles, said there had been confusion over Roberts' dismissal at Brightlingsea and the referee's report had not been received prior to the Diss game, so the club had been unable to clarify the matter. He said the club had checked Roberts' availability with Norfolk FA but without the referee's report they had no record of a suspension.

Bayles added: 'We fully accept that he should have been suspended and that we made an error in playing him.'

There will be no appeal over the decision and Premier Division leaders Dereham briefly dropped back to 69 points – before restoring their total last night with a dramatic 2-1 win at Ely City.

There could be repercussions from that game, too, as the referee was forced to take both teams off the field for 20 minutes early in the first half when a skirmish broke out in the tunnel area following the dismissal of Ely's Darren Coe and Dereham's Shaun Bammant.

When tempers had been allowed to calm play resumed and Ely took the lead in the 39th minute when an unmarked Adam Murray headed home at a corner.

A superb save from Andy Wilton stopped Ely getting a second soon after the interval and Dereham equalised in the 58th minute when Adam Gusterson headed in Aaron Kay's corner.

Sam Borrer grabbed the winner in the 79th minute with a firm right-foot shot after a strong run.

Wisbech kept the pressure on the leaders when a lone Danny White goal proved enough to beat Mildenhall.

Norwich United beat Brantham 3-1 while Diss lost 2-1 at Hadleigh despite a goal from Adam Burroughs.