London: Young children looked after by middle-class grandparents develop better vocabulary than those in nurseries, a study has revealed.

They are significantly ahead by the age of three due to the amount of one-on-one time they spend with a loving adult.

The head start relates more to children who live in better-off households, where grandparents tend to have higher levels of education and are likely to be better carers than formal carers in relation to the early learning of new words.

For less well-off homes, the researchers believe that while children are not put at a "significant" disadvantage in terms of vocabulary, their grandparents "may not confer the advantages" that formal care provides.

A similar distinction was suggested in social development.

By contrast, children from disadvantaged backgrounds were thought to receive a slight benefit from formal childcare.

The findings were published in a review of childcare studies by researchers from the Institute for Fiscal Studies, Bryson Purdon Social Research, Essex University's Institute for Social and Economic Research and the National Centre for Social Research.