EastEnders and Coronation Street look to be on course for a rare head-to-head clash as TV bosses finalise their schedules.
ITV is lining up an extra half hour of its Weatherfield drama at 8pm on Monday June 23, which will go up against the established edition of the BBC1 soap which is usually in the same slot.
Insiders at the BBC said the move will split the soap audience, and one source said it appeared to be "unnecessarily aggressive scheduling" on the part of the commercial channel.
However, ITV has played it down saying it is simply fitting programmes around World Cup matches.
Programme chiefs will finalise their schedules later today. In one draft version ITV has placed an edition of Corrie at 7.30pm which will continue until 8.30pm - giving the show a half-hour overlap with its Albert Square rival.
Last week ITV had simply held the spot by saying the programme at 8pm was still to be announced.
Schedulers on the main channels have tough decisions to make as they work around a range of fixtures in Brazil over the next few weeks.
The BBC source accused ITV of "deliberately creating a clash" by extending the show into an established EastEnders slot.
But an ITV spokeswoman said: "We have two World Cup matches that day so that's where it is."
The slot is unlikely to change at the final handover of schedules.
In recent years there have been behind-the-scenes rows between the channels over the scheduling of Saturday night entertainment shows such as Strictly Come Dancing and The X Factor when they have overlapped, although these have become less frequent.
Other occasional disputes about scheduling have been caused by the screening of football matches which have left TV bosses with little room to manoeuvre.