While on trial at Teesside Crown Court Wednesday, Gemma Fennelly of Hartlepool admitted to using the drug to give her 22-month-old son a fatal overdose in September 2005, the Sun reported.

Fennelly is on trial for the second time on a charge of manslaughter by gross negligence. Her first trial was halted to provide time for key forensic tests.

Those tests reportedly showed traces of both heroin and cocaine in the hair taken post-mortem from her son, Mitchell Bate.

The toddler's father, Mark Bate, was cleared of all charges on Wednesday after it was revealed that he was not living with the baby at the time.

The Sun said Fennelly was granted conditional bail until her case comes up for sentencing on May 3.