The number of babies dying from unexplained causes, including cot death, has fallen to the lowest level since records began.
There were 254 unexplained infant deaths in England and Wales in 2010, down from 440 in 1996, according to figures from the Office for National Statistics (ONS).
The rate of unexplained infant deaths has also fallen to an all-time low.
In 1995, when the figures were first complied, the death rate was more than 0.6 per 1,000 live births, but in 2010 it fell to 0.35.
Unexplained infant deaths include sudden infant deaths and those where the cause of death is not ascertained or unknown after a full investigation.
The figures showed that unexplained death accounted for 8% of all infant deaths in 2010.
The figures also showed that babies were more likely to die from unexplained causes when cared for by a single mother rather than by a married couple.
The rate of unexplained infant deaths for babies registered to the mother only was 1.18 per 1,000 live births, compared to just 0.14 for babies registered to a married couple.
Of the unexplained infant deaths in 2010, just over a third occurred in the winter months, compared to 21% between June and August.
The ONS also found that babies born in London were less likely to die from unexplained causes than those in the north west of England. In the capital, there were 0.21 deaths per 1,000 live births, compared to 0.53 in the north west.
Figures released by the Office of National Statistics reveal that the north west has the highest rate, 0.53 per 1,000 live births, significantly higher than London which has the lowest at 0.21.
The Foundation for the Study of Infant Deaths’ (FSID) chief executive, Francine Bates OBE, said: “Although we have seen a small reduction in the number of deaths across England and Wales the figure for the north west is extremely concerning. The region has had the highest rate for the last seven years.
“We know that smoking is a major risk factor for sudden, unexplained infant death and the smoking rate in London is the lowest in the UK but the rate for the north west is above the national average.
“FSID has pledged to halve the numbers of unexplained infant deaths by 2020 and public health agencies in the north west and also in Wales, which has the second highest rate, can help us achieve our goal by ensuring that ‘reduce the risk’ campaigns, with a focus on the dangers of smoking, are an on-going local priority.”