ITV1 has been hit by one of its worst ratings slumps on record, with 10% fewer viewers watching the channel than in the opening two months of 2004.
I'm A Celebrity winner Joe Pasquale was a ratings winner late last year
The drop could be due to ratings winner I'm A Celebrity... Get Me Out Of Here being screened in January and February of last year, but not in 2005.
Other programmes such as The Bill and The Royal are not proving as popular.
The only other channel to suffer a greater dip was BBC Two, which saw a 12% year-on-year fall in its figures.
Analysts have also highlighted the importance that the jungle-based reality show has had for ITV1's audience share.
The finale of December's series attracted four million fewer viewers than the previous run in early 2004, and there are plans for ITV to unveil new programmes to woo back the youth audience.
Celebrity Love Island is a new reality TV format which is expected to air in the summer.
A spokeswoman for ITV said it was important to look at the station's portfolio of channels, including ITV2 and ITV3.
"Last year we had the most successful I'm a Celebrity... Get Me Out of Here! We don't have that this year. We are still the most popular channel in peak hours," she said.