The most recent figures for conception by girls aged 13-15 show a rise to 9.4 pregnancies per 1,000 in 1996, compared with 8.5 per 1,000 in 1995, the Office for National Statistics revealed.

More than 75% of those pregnancies were among 15-year-olds, and over half of all under-age conceptions were aborted.

Single mothers constant

The survey, called Birth Statistics 1997, also found that marriages fell to their lowest level since World War I last year, with a corresponding increase in children born to unmarried parents.

The number of children born out of wedlock rose sharply from 23% 10 years ago to 37% in 1997.

The number of registered single mothers - suggesting one-parent families - has remained constant around the 50,000 mark since 1987, while there has been a significant increase in children registered to unmarried parents co-habiting.

Numbers rose from 75,000 births jointly registered by unmarried parents 10 years ago to 142,000 in 1997.

Decline resumed

A vast majority - 98% - of births occur in hospital, rather than at home, and 99% of those take place in a National Health Service hospital.

There was an increase in conceptions in England and Wales of 3.3% to 816,000 in 1996, representing the first rise since the birthrate went into decline in 1990.

The decline resumed in 1997.