World Aquatics Championships: British divers Tonia Couch and Lois Toulson struggle
Olympians Tonia Couch and Lois Toulson missed out on automatic qualification for the 2018 World Series by finishing seventh in the synchronised 10m World Championship final in Budapest.
The British divers, who were fifth at Rio 2016, were seeking a top-six position in the event.
Great Britain totalled 300.48 from their five routines, as USA (306.96) claimed sixth.
China took gold, North Korea silver and Malaysia bronze.
In the men's individual 1m springboard final, James Heatly was ninth and Ross Haslam 10th.
Haslam will return for the individual 3m competition on Wednesday, which will also feature Jack Laugher, who won Olympic silver in the event at Rio 2016.
Toulson won World silver in the mixed 10m platform event on Saturday alongside Matty Lee, but could not repeat that form in the women's event.
Couch and Toulson added their voices to the growing concern over the low poolside temperatures, which many athletes have stated is impacting their performance.
"We were very cold during that [preliminary round in the morning], but just tried to concentrate and improved from the morning in the final," Toulson told BBC Sport.
Couch, who was competing in her seventh World Championships, added: "I thought we dived pretty well, but it is freezing.
"Our physio has been filling plastic bottles with hot water and we've had those under our arms and on our legs and spending a lot of time in the hot showers."
While Couch's Championships are over, Toulson will return for the women's individual 10m platform event which begins on Tuesday.
Monday's action will see Olympic bronze medallists Tom Daley and Dan Goodfellow bid for their first World Championship medal together in the synchronised 10m platform event.