The scheme, part of Healthy Start, sees involves vouchers which can be exchanged for milk, infant formula powdered milk and fresh fruit and vegetables. This new scheme replaces the Welfare Food scheme which gave milk and infant formula to families.

For the first time all pregnant teenagers - a group known to be nutritionally vulnerable and at risk of having babies with a low birth weight - will benefit.

The scheme aims to improve nutrition, give children the best start in life and reduce health inequalities.

Public health minister Caroline Flint said: “Poor diet can have a real impact on people's health. We want people to have the best possible opportunity to eat healthily.”

It is expected that an estimated 75,000 pregnant women and children under four in the north-west of England will benefit from the vouchers, worth £2.80 each.

Free vitamin supplements will remain an important part of the new scheme.

Qualifying pregnant women and children over one and under four will get one voucher every week, and children under one year old will get two vouchers a week.

Vouchers can be spent with participating retailers - including small businesses and milkmen as well as larger supermarkets and chemists.

Around 20,000 individual retailers across the UK have already signed up to participate in Healthy Start - more than had signed up to the welfare food scheme.

Flint said: “This new scheme will not only provide greater choice of healthy food, but will also mean that children can get milk and fresh fruit and vegetables from the cradle up, helping to give them the best possible start in life.” Dr Peter Aggett, paediatrician and chair of the North-west Food and Health Action Plan, said: "The old scheme discriminated in some ways against mothers who wanted to breastfeed.

"We all know how important it is to start a healthy diet at a young age - the Healthy Start programme will encourage this, particularly amongst low income families, as well as putting them in touch with health care professionals who can offer them extra support."

Ian Grace, regional director for Morrisons in the North said: "We believe the scheme is a great way of encouraging customers to eat a balanced diet."

Women qualify for vouchers if they are on benefits or pregnant and under 18. Anyone already receiving milk tokens through the Welfare Food Scheme will automatically get Healthy Start vouchers instead. Further information at www.healthystart.nhs