Unilever is hoping to grow the concentrated liquid category in laundry with new bulk packs of its key brands and a £12m supporting campaign.

It is introducing "big pack" versions of Persil Small and Mighty and Surf Small and Mighty this month in 28-wash, 54-wash and 85-wash formats (rsp: £4.30-£14.99). The newcomers will replace the existing 20 and 42 wash formats.

Unilever expected the larger packs to encourage more consumers to switch to liquids and offer better value "in a more environmentally friendly product". The above-the-line push will kick off later this year.

"Concentrated liquids are the fastest-growing ­format in laundry and will continue to be the driver in the category as customers move from traditional ­powder," said Dani Ross, brand manager for Persil.

"Laundry liquids are also more compact, offering ­better shelf efficiency while driving profits for retailers due to high margins."