However, by this time the tide was turning and many leading educators were questioning the effectiveness of mixed ability teaching.

BBC: Setting, streaming - how schools teach

In chronic liver disease, cells are lost, reducing the effectiveness of the liver and leading to ill health.

BBC: Excessive drinking can lead to cirrhosis

Bernd Kosch, green IT advisor, Fujitsu Technology Solutions: Among the various green benefits of the cloud computing paradigm, there is one which is exceptionally striking: cloud computing enables small and medium enterprises (SMEs) to take full advantage of very large scale data centre technology, including the latest, most energy-efficient hardware provided in the shortest refresh cycles and leading facility-related infrastructure with advanced power utilisation effectiveness.

FORBES: Cloud Computing's Hidden 'Green' Benefits

Commenting on the survey's findings, Dr Penny Woods, chief executive of the British Lung Foundation, said the significant decline in the numbers of people smoking in Britain over the last 40 years was "a testament to the effectiveness of combined legislation and awareness raising in tackling what is Britain's leading cause of preventable illness and premature death".

BBC: ONS survey: Smoking halves in 40 years

For the past 25 years he served as Senior Research Scientist at ETR Associates in California, USA. Over his professional career, he published the most definitive systematic reviews on the effectiveness of sex, relationships and HIV education in schools and is widely recognised as the leading world expert on sex, relationships and HIV education curriculum standards.

UNESCO: EDUCATION