The Food Standards Agency has been accused by campaigners of "chickening out" of banning additives linked to hyperactivity in children.
Artificial colourings were found to affect children's behaviour
FSA board members agreed to wait for the European Food Safety Authority to make a decision on the use of artificial food colours in food.
But the watchdog called on industry to act quicker to remove additives in response to concerns.
A recent UK study found a link between additives and hyperactivity.
The FSA-funded research, published at the beginning of September, found impulsive behaviour and loss of concentration in children who had consumed a drink containing a mixture of additives.
The FSA then issued updated advice that eliminating the artificial colourings from the diet might have some beneficial effects in hyperactive children.
But critics said it did not go far enough.
Several environmental and children's campaign groups, including the National Union of Teachers, called on the watchdog to extend that advice to all children.
Professor Jim Stevenson, who carried out the research, told an open meeting of the FSA board, he believed the effect of the additives posed a threat to psychological health.
The FSA said the evidence was not strong enough to justify a ban and it would wait for the European Food Safety Authority to make a decision on use of additives in food.
FSA chairman Dame Deirdre Hutton told the meeting they would make current advice "more explicit" and more helpful for parents.
She added: "I think there is a general astonishment that industry has not responded more quickly to consumer demand in terms of taking colours out of their food."
Richard Watts, spokesman for the Children's Food Campaign, called for the additives to be banned.
"Professor Stevenson, who undertook the study on additives, told the FSA that there was the evidence necessary to ban these additives because they do pose a threat to health," he said.
"Parents will be furious that the FSA has chickened out of taking this vital step to protect their children."
Previous research had made a link between additives and hyperactive behaviour, but in the Southampton study researchers looked at wider age range of children not all of whom had behavioural problems.
Sunset yellow (E110) - Colouring found in squashes
Carmoisine (E122) - Red colouring in jellies
Tartrazine (E102) - New colouring in lollies, fizzy drinks
Ponceau 4R (E124) - Red colouring
Sodium benzoate (E211) - Preservative
Quinoline yellow (E104) - Food colouring
Allura red AC (E129) - Orange / red food dye
The children were randomly given one of three drinks, either a potent mix of colourings and additives, a drink that roughly matched the average daily additive intake of a child of their age, or a "placebo" drink which had no additives.
Mix "A", with the high levels of additives, had a "significantly adverse" effect on hyperactivity compared with the inactive placebo drink.
Between 5% and 10% of school-age children suffer some degree of ADHD - attention deficit hyperactivity disorder - researchers suggest, with symptoms such as impulsiveness, inability to concentrate and excessive activity.
The researchers concluded there were many influences on hyperactivity in children but additives was one factor that could be removed.
The European Food Safety Authority (EFSA) is considering the research as a matter of urgency and will be making an initial response within the next month.
Julian Hunt, communications director of the Food and Drink Federation, said industry had been responding in recent years.
"The development of additive-free products is one of the biggest trends in the grocery market this year.
"And I have no doubt that companies which have not already completed their reformulation work will be accelerating their efforts in wake of the FSA¿s study."
He added the FSA response had been proportionate and evidence-based.