Most of us last tasted it at the age of 10 and have hardly seen one since, let alone gone shopping for one – but that was before it acquired the extra sweetness of being politically incorrect.

It's the square cake with marzipan on the outside and at least two colours of sponge on the inside, with jam at the joins. Aah, you remember it now.

Kipling Cakes is probably the biggest baker of Battenberg in the UK and its parent company, Premier Foods, has been busy correcting reports that the future of the sugary treat is threatened if the Food Standards Agency (FSA) succeeds in banning six artificial colourings, as proposed last week. None of the six is used in the Kipling version.

However, some makers clearly still find them necessary, because Battenberg Cake was on the endangered species list issued by the food industry when the FSA called for a voluntary UK ban on the six dyes to take effect in the UK by the end of 2009. It also called on its bosses, the UK Government, to try to get the dyes taken off the EU approved list on which they are given internationally-recognised numbers and quality standards – E110 for Sunset Yellow, E102 for Tartrazine, etcetera.

This is why they have become infamous as "E numbers". But
E numbers are not intrinsically bad. The list includes bicarbonate of soda, salt, Vitamin C and other "natural" products which are sometimes added to food in un-natural proportions.

However, the debate over E numbers has been one of those battlegrounds – like climate change – where the absolutely convinced come up against the resolutely sceptical and hardly anyone ever changes their mind.

The hard evidence against the substances in question is still pretty thin, despite 30 years of suspicion.

A Southampton University report, last March, did seem to show that kids with hyperactive tendencies became even more so when they consumed drinks containing various combinations of colourants used in pop, marshmallows, iced cakes, jelly beans, custard powers, orange potato snacks and so on.

But the FSA and a couple of Euro-agencies commissioned the study and there has been criticism of its design. For one thing, it identified a "cocktail effect" rather than pinning down particular reactions. And although benzoates, commonly used in soft drinks, were in the mixtures tested, they are exempt from the proposed ban because they are useful preservatives.

The EC's advisers did not think the Southampton findings warranted any action. And the FSA thought a mild warning to parents was enough until the organically-fed end of the media opened up on it for gambling with children's health.

There are many more E numbers still to be reviewed. But the six in question are particularly vulnerable because they do nothing for food except perk up its appearance. The food and drinks industry – seeing the way the wind was blowing – has been voluntarily replacing colour-only additives with natural substitutes for some time. But makers are still looking for satisfactory new ways to put long-shelf-life red into the Sheffield-made Frys Turkish Delight, pea-green into Batchelors Mushy Peas,
orange into Gatorade and the pink and yellow into some Battenberg Cakes.

The FSA's significant adjustment of position sets a deadline which it hopes will gee things up. It puts the Government under pressure to level the playing field by getting the rest of Europe to follow suit. Otherwise, UK shops will still be free to sell goods which UK factories cannot supply. The voluntary target for the UK does not need approval from anybody else. It is up to the FSA to see what it can thrash out with the industry. But the industry is likely to capitulate.

As one sweet-maker said yesterday: "Obviously we think the additives are safe, or we wouldn't be using them in the first place. And people do buy with their eyes. But whatever we think of the FSA, we have to take account of what the customers think, in the light of all that has been said."

A blogger called Chicken Yoghurt commented on the FSA announcement: "Forget citizenship tests. Anyone who can't cram down half a bar of Battenberg with a mug of sugary tea should be deported immediately. And that includes UK citizens."

Chicken Yoghurt may have had his tongue firmly in his cheek, but there was some reasonably serious argument along similar lines in the blogs and bars.

Up until the FSA acted, there was a lot of popular support for the theory that E-numbers were a bad thing – ask any teacher about it.

But once the deed was done, it was time to switch to the other side. When did anyone ever die from E numbers? What was it to the FSA if Turkish Delight was our secret vice? What would fish and chips be without mushy peas?

After trawling through the library of recommendations on the subject it took Ben Goldacre, a doctor who blogs at badscience.net, to point out how we are routinely bamboozled.

He said in the Guardian last weekend: "These decisions are a mixture of whim and politics. They're vaguely informed by research, but only partly."

On the other hand, not everything is right just because we have lived with it for a while. E numbers have been banned before, after being found retrospectively guilty of poisoning the customer.

The Food & Drink Federation traces the history of additives back to saltpetre, for preserving, and spinach extract, for colouring soups – ingredients Mrs Beeton would have used.

But most of those we are now getting all nostalgic about are extracted from coal tar and were invented in the 20th century for the textiles industry – then adopted by the food business as it moved from kitchens
into factories.

Not everything we get nostalgic about is very old. Professor Ralph Blanchfield, an MBE for his work for food science, was working for Batchelors when mushy peas were invented, in the 1960s.

At first, they were just a problem, he reveals – a sign that a batch of dried peas had gone wrong in the processing.

When the boffins finally worked out what was happening, they turned the accident into a deliberate process, added a touch of tartrazine to put some colour back into the mush, and started an instant tradition.

Fry's Turkish Delight goes back a bit further – to 1914. And Battenberg was invented in Germany in the 19th century and named after the village bearing the name of the family of which the Mountbattens are an Anglicised branch. Battenburg, although a common spelling,
is the wrong one.

It is unlikely they will all disappear. Rowntree's of York eventually found ways of producing the whole original range of Smarties – including the tricky blue one – without using chemical colours, after all. Cadburys has promised to crack the Turkish Delight problem by the end of this year. Mushy peas can probably live off loyalty, although they might be a bit greyer.

But there may be consequences yet to be discovered. What goes into all those rainbow sweets eaten at Indian and Greek weddings, for example? A few phone calls from here failed to find any maker who admitted using the offending additives, but it would not be surprising if some do.

Bronek Wedzicha, professor of food science at Leeds University, summed up yesterday: "It's probably all fair enough. But I do get irritated when people say it doesn't matter because it is only about colour. Colour is important to us. A discoloured vegetable might be perfectly healthy but you don't want to buy it.

"You can argue that drinks and confectionery are not vital. But it is also fair to ask, what would life be without Smarties?"