Fewer than one in a hundred women follow government advice to breastfeed exclusively for the first six months, figures show.
Breastfeeding is becoming more common
The Infant Feeding Survey shows in 2005 76% of UK mothers started out breastfeeding - up 7% from 2000.
However, most resort to formula within weeks, and fewer than half still breastfeed by the time their child is six weeks old.
By six months, just one in four are still breastfeeding.
The survey, which has been carried out every five years since 1975, also found that well educated, professional women aged over 30 who were first time mothers were the most likely group to breastfeed.
Professor Denise Lievesley, of the Information Centre, which produced the study, said the overall message was positive as more women were breastfeeding for longer.
She said the survey would help health workers to target resources at those on which they would have the most impact.
"Overall, it is encouraging to see that more mothers than ever before are starting out breastfeeding their babies and, while there is a sharp drop-off, more are continuing to breastfeed for longer."
The figures were released on the first day of National Breastfeeding Week, which will see the launch of a breasteeding manifesto in Westminster on Wednesday.
Breastfed babies five times less likely to end up in hospital than formula-fed babies with gastroenteritis
Breastfed babies half as likely to end up in hospital with respiratory disease in their first seven years of life
Breast milk protects against diabetes and obesity
The manifesto, supported by 183 MPs and various celebrities, aims to promote breastfeeding and create an environment in which women feel more comfortable about doing so.
Alison Baum, from the Breastfeeding Manifesto Coalition, said: "Women need to be able to feel confident and comfortable to breastfeed wherever they need to.
"Babies need to feed at all sorts of times, and you can never know when a baby is going to need to feed
"It's the most natural thing in the world, and the evidence for the health benefits are huge, so we should be doing all we can to support women."
She said most women who breastfed in public did so discreetly, with people not realising.
But she said: "There are the odd cases where women are thrown out of restaurants and cafes."
It is illegal in Scotland to ask someone to stop breatsfeeding in an establishment that normally serves food.