Big Brother votes have fallen sharply compared to last year as the show reaches its half-way mark.
Tania is favourite to be evicted this week
Voting figures are 40% down compared to the same point last year, when housemate Spencer Smith was voted out.
The drop in viewing figures comes amidst media reports the UK version of the show has become dull and that viewers have turned off.
With five evictions having taken place already, 3.87 million votes have been cast, compared to 6.5 million last year. Eight contestants are left in the show, vying for the £70,000 first prize.
Channel 4 said 1.73 million votes were cast by viewers last week, compared with 2.75 million in the same week of the series last year.
The drop in votes may be mitigated by the fact that the number of votes for last year's eviction, that of Spencer Smith, was the second highest in Big Brother UK history.
Producers have tried to keep the show popular with new features in its fourth series.
On Friday they evicted two people instead of one, with both Jon Tickle and Federico Martone kicked out of the house.
On Monday they swapped Scottish housemate Cameron Stout with Gaetano Kagwa, a Ugandan contestant from the first pan-African series of Big Brother. The swap is expected to last a week.
Gaetano Kagwa has swapped places with Cameron
The remaining three female contestants in the Big Brother house each face possible eviction from the programme this Friday.
Steph Coldicutt, Nush Nowak and Tania Do-Nascimento have all been nominated for possible eviction by fellow housemates.
According to bookmaker Ladbrokes, Tania is the 1/3 odds-on favourite to be evicted from the house on Friday, with Steph at odds of 3/1, and Nush 8/1 to go.
Last year's Big Brother was won by Kate Lawler, who is now a presenter on Channel 4's breakfast programme Rise. She was the first woman to win the show.