A mother and daughter have admitted to a Christmas poison plot to kill her husband by slipping antifreeze in his Lambrini.

Jacqueline Patrick, 54, pleaded guilty to two counts of attempted murder of Douglas Patrick at Inner London crown court. She made two attempts on her husband’s life: in October 2013 and on Christmas Day 2013.

Their daughter, Katherine Patrick, 21, admitted to inciting another to administer a noxious substance. Both have been bailed ahead of sentencing on 2 November.

Police began an investigation after doctors at King’s College hospital found Douglas Patrick, 70, of Crystal Palace, south London, had been poisoned with antifreeze when he was admitted on Boxing Day 2013.

After he emerged from a coma on 8 January 2014, he told police all he remembered was drinking two glasses of cherry Lambrini on Christmas Day and going to bed feeling more drunk than he had expected. He added that he suffered a similar episode the previous October. Jaqueline and Katherine Patrick were arrested the next day.

Evidence soon began to stack up against them. Days earlier, as an ambulance took Patrick to hospital from the family home, his wife had shown paramedics a typed note, which she claimed he had written, asking to be allowed to die with dignity if his heart stopped.

When doctors told her her husband had been poisoned, she replied that she thought he might have drunk a blue liquid by mistake. The hospital, finding it strange that she had not volunteered this information earlier, called police.

The pair were initially charged with three counts of attempted murder – with the incitement charge added later – after police found suspicious text messages exchanges between the pair. One said: “I got the stuff I will give him some later delete txt tell no one ok.”

Interviewed by police, the mother admitted searching for anti-freeze poisoning on the internet, claiming that her friend’s dog had accidentally consumed some. But when officers tracked down the “friend”, he said he had never owned a dog.

The prosecution agreed to accept a plea of two counts of attempted murder from Jacqueline and the incitement count from Katherine. The remaining charges were left to lie on file.