Phosphates & the Unilever/Henkel Persil carve-up of the mark
The way phosphate/nitrate regulations work in the UK, the Detergent Industry was set a quota which it must stay under, rather than the complete elimination of phosphates from their products. As a result, a few products do still contain phosphates, but the vast majority don't.
Phosphates seem to have been restricted to the tablet detergents only and only two manufacturers continue to use them : Unilever and McBride (an ownbrand/private label producer).
Unilever products with phosphates:
Surf Tablets
Persil Tablets
ALL other Unilever formats are phosphate free i.e. Powder, Liquids, LiquiTabs (dissolvable pouches).
Unilever's formulation for Persil Tablets in Ireland is different from the UK market as the phosphate regulations are tighter here. Persil tablets marketed here are foil-wrapped and slightly larger than their UK counterparts, in fact, they're the same product as Skip tablets in France, just with a different logo. Otherwise, the marketing and packaging is identical.
I have noticed NO difference in how the two formulas perform. They both provide brilliant results.
As for the Unilever vs. Henkel division of the Persil brand.
Unilever own the rights to the Persil Brand in : The UK, Ireland, France and New Zealand only.
Everywhere else, Persil is a Henkel product.
This agreement dates back to the early 20th century when Henkel sold rights to the Persil brand to Lever Bros Ltd in the markets listed above. That agreement still stands and it's highly unlikely to change as Persil is a MASSIVE brand for Unilever in the UK and Ireland which is effectively its home turf.
Persil in Ireland for example outsells Ariel 3 to 1 ! It's an extremely well established brand.
The Henkel and Unilever Persil products share no R&D or formulation details anymore. They're two completely separate product lines by two totally different companies. However, they are both marketed as TOL detergents in their respective markets and go head-to-head with Ariel, so they're likely perform similarly well.
Persil in France is used to market a 'natural' range of detergents by Unilever. They're a specialist product that contains Savon de Marseilles (traditional soap from the South of France). They smell great though!
The main Unilever TOL brand in France is Skip. This is pretty much identical to Persil in the UK or Ireland (other than that it's also entirely phosphate free). It comes in all the same formats and has very similar marketing.