The girl was still in primary school when she conceived. She gave birth to a daughter over the weekend and both are said to be in good health. (Agencies)
The young couple, from north London, who posted a photo of their new arrival online, have vowed to stay together as a family, 'The Mirror' reported.
The girl, who cannot be named for legal reasons, is five months younger than the UK's previous youngest mother.
The girl's 27-year-old mother has becomes one of the Britain's youngest-ever grandmothers.
"The baby's mum and dad have been in a relationship for more than a year, so this isn't a fleeting romance. They intend to stick together and bring their daughter up together," a source was quoted as saying by 'The Sun'.
"Both sets of grandparents are incredibly supportive. It's a very difficult situation because the parents are both so young - but their families are right behind them," the source said.
In 2006, Tressa Middleton, the Britain's previous youngest mother, gave birth in Edinburgh aged 12 years and eight months.
Lina Medina from Ticrapo, Peru, became the world's youngest mother in 1939, the report said.
She gave birth to a son at the tender age of five years and seven months.
The girl was still in primary school when she conceived. She gave birth to a daughter over the weekend and both are said to be in good health.