The children of mothers who work full time are less healthy than those whose mothers stay at home, according to new research.

Almost two out of three mothers with children under five work in Britain with numbers expected to rise, but an authoritative new study has shown this can affect children’s health.

Encouraging mothers to return to work has been a key policy of the Labour Government and Patricia Hewitt said in 2004 when she was Trade and Industry Secretary that mothers who do not return to work were ‘a real problem’.

Researchers found children whose mothers worked were more likely to be driven to school, to watch more than two hours of TV a day, and have sweetened drinks between meals. Children of mothers who worked full time also ate less fruit and vegetables, the study suggests.

Middle class families suffer the same problems as the findings remained similar even when household income was taken into account, the paper said.

The research, on more than 12,000 British children aged five, was published in the Journal of Epidemiology and Community Health.

The research, from a team at the Institute of Child Health in London, found although children whose mothers worked full time ate less fruit and vegetables, the link disappeared when looking at mothers who worked part-time, the research showed.

However, there was no difference between working mothers and non-working mothers on the level of exercise a child took or whether they mainly snacked on crisps and sweets between meals.

The researchers noted that around 60 per cent of women with a child aged five or younger in the UK or USA are employed, adding in the study: “Time constraints may limit parents’ capacity to provide their children with healthy foods and opportunities for physical activity.

“Although we found that flexible work arrangements were not detrimental, they are unlikely to be important in helping parents support the development of positive health behaviours in their children.”

A total of 30 per cent (4,030) of the mothers had not worked since the birth of their child but the rest were employed.

They typically worked 21 hours per week and for 45 months.

The mothers were questioned about the hours they worked and their children’s diet, exercise and activity levels when the youngsters were five.

The findings showed that after factors such as mother’s education, socioeconomic circumstances and ethnic origin were taken into account, children were 55 per cent more likely to be driven to school if their mother worked 21 hours or more a week.

They were 33 per cent more likely to watch more than two hours of TV a day, than children whose mothers did not work at all.

Jill Kirby, director for the Centre for Policy Studies said: “The overall picture seems to confirm earlier studies where mothers are more rushed and trying to deal with the demands of working life they are less likely to be able or motivated to ensure their children have a healthy diet and lifestyle.

“The answer is not more government regulation but more choice for families to enable them to choose parental care over childcare where they want to and to relieve some of the pressure mothers are put under to place their children into formal care instead of looking after them at home themselves, especially in the early years.”

Sue Palmer, an education consultant and writer, said she was not surprised about the new research.

She said: “The simple common sense explanation is that the parent knows the child so they know the best way to persuade it to behave and teach good habits. If you don’t know your little one that’s not so easy.

“If parents are close to those children in those first three years, they can set up default habits of eating, activity, play, bedtime routines, mealtime rituals which can help to counter the effects of consumer messages that children are often getting, very often more towards junk food.

“If you can set up default habits when the child is very small through the close relationship, it seems there is a good chance those habits can continue. If they aren’t set up early, it is more difficult to set up these habits.”