A two-year-old was the youngest child at risk of being forced into marriage, one of 250 children aided by the UK's Forced Marriage Unit, according to new statistics.
Around 80 of those helped were under the age of 15 when authorities had intervened, and statistics identify those between the ages of 16-25 as being the age most at risk.
Anup Manota, project manager at forced marriage charity Karma Nirvana, told Huff Post UK he believes this is the "tip of the iceberg".
He said: "Many of the victims have in fact been promised to someone from birth, or maybe even before birth, with families saying the daughter or son is promised to another family in exchange for business or land. We are finding that is a common occurrence.
"The child grows up and they do not realise they have a choice. We have been doing more and more work in primary schools, it has to be done tactfully but teachers need to know the risks, to be sensitive when children from these communities are taken away for extended periods."
The FMU, a joint initiative of the Foreign Office and the Home Office, intervened in 1,485 cases last year, with 82% were female and 18% male. Many forced marriages go unreported.
Home Office Minister for Crime Prevention, Jeremy Browne, said on publication of the new statistics: “Forced marriage is a devastating form of abuse that is absolutely unacceptable in our society.
"The new figures show an alarming number of victims, including the young and vulnerable.
"It is vital we protect them. By criminalising forced marriage the government is sending a strong message that this terrible practice will not be tolerated.”
Other statistics show more than 20 gay or lesbian potential victims of forced marriage, and more than 100 disabled people.
The country of origin of 46% of the victims was Pakistan, 9.2% from Bangladesh, 8.7% were born in the UK. Other countries included Turkey, Afghanistan, Sri Lanka, Nigeria, Somalia and the United Arab Emirates.
Karma Nirvana's Manota observed: "It's not a cultural or religious matter, it's abuse, pure and simple.
"Cases like the murder of Shafilea Ahmed really brought honour killings and forced marriages into the spotlight, when you go into communities to talk about those issues, people know that case. We know there are thousands more cases out there."
Freedom Charity launched a "Forced Marriage" app for iPhones to coincide with the release of the figures, with founder Aneeta Prem calling it "the 999 of apps." She added: "It is more important than ever that everyone in the UK is aware of the warning signs of a forced marriage."