Analysts say viewers and advertisers have been unsettled
ITV is to move its late news bulletin to a regular slot at 10.30pm after winning approval from TV regulators.
The Independent Television Commission (ITC) said having a regular, fixed time for the weekday late evening bulletin was in viewers' interests.
Three years ago ITV brokered a compromise to run its bulletin at 10pm - head-to-head with the BBC's Ten O'Clock News - at least three times per week.
But analysts said the move was unsettling for viewers and advertisers because the news was never on at a fixed time.
There will be no change to the scheduling of ITV's 6.30pm news, which meets the network's requirement to provide a half-hour national news bulletin in peak time, the ITC said in a statement.
David Mannion, editor of ITV News, said: "The new schedule presents an exciting opportunity to produce a new and reinvigorated programme.
"We firmly believe that a fixed time slot five days a week will make the
programme more competitive and more attractive to viewers."
The channel has been locked in a battle for viewers since the BBC moved its main evening bulletin from 9pm in October 2000.
The BBC claims to have come out on top overall, but on some occasions - especially when popular programmes were on immediately beforehand - the ITV news attracted a larger audience.
Nigel Pickard, ITV director of programmes, said: "This decision is absolutely in the public interest.
"Head-to-head news on the two main channels has not served viewers well.
"This solution enhances choice for news audiences and restores a fixed slot for ITV's main evening bulletin."
ITV moved its news from 10pm to 11pm in March 1999, and the BBC moved in to fill the vacant slot.
But ITV was forced to switch back after the ITC found its replacement was attracting too few viewers.
ITV made a temporary move to 9pm during the war in Iraq, and has kept a short update at that time despite moving the main bulletin back to 10pm.