In 1996, 65 babies were abandoned, according to Home Office statistics.

That figure compares with 22 a decade earlier.

BBC correspondent Tim Hammond: The babies are left to survive alone

While 52 of those mothers were traced by police, the rest never came forward.

In many cases the babies are left to survive on their own, often wrapped only in a blanket, outside hospitals, phone boxes, or churches.

Earlier this month "Baby Callum" was buried after he was discovered having been dumped in a bin-bag in Warrington in March.

He was only a few hours old when abandoned and died of asphyxiation.

Cheshire Police believe the mother was young and gave birth without medical assistance.

But she has remained silent despite police and press appeals.

It is a typical, although rare, case.

Training

More than 50 mothers were traced

Many police forces are now training officers how to deal with abandoned babies and their mothers.

Often the women can be suffering post natal depression or feelings of inadequacy.

In some cases, mothers may see abandoning their child as an alternative to abortion or leave their baby believing the infant will have a chance of a better life.

Doctors have no firm conclusions as to why the number is increasing although they believe teenage pregnancies together with inadequate sex education could be factors.

Britain has the highest teenage pregnancy rate in Europe.

Sex education

The Family Planning Association, which is organising a week of events in August to raise awareness of the need for better sex education, says there is no evidence to suggest teenagers are more likely to abandon their babies than other women.

A spokeswoman said: "People feel overwhelmed and unable to cope. If they are unsupported in the pregnancy, they feel they are unlikely to be supported once the baby is born."