Sky can't launch a children's channel themselves as they're bounded by a contract with ViacomCBS due to the Nickelodeon UK joint venture, Sky currently owns 40% of Nickelodeon UK Ltd. However, Sky has a VOD service for kids called "Sky Kids" which includes streaming content from Nickelodeon, Nick Jr, Nicktoons, Cartoon Network, Boomerang, and Cartoonito etc. plus some additional commissioned and acquired content that complements (and doesn't compete) with these channels.
In 1996 before Fox Kids launched (100% owned by News Corp at the time but reduced to 50% following the Saban partnership that was announced that November, News Corp also owned 40% of Sky), Viacom threatened legal action to stop Fox Kids launching in the UK, but nothing came of it, likely due to News Corp's stake in Fox Kids was reduced.
There was also another Viacom/Sky conflict that flared up in 2001 when News Corp was planning to buy Saban's 50% in Fox Kids, as Saban wanted out of the venture. Fox Kids (and Saban Entertainment) was subsequently sold to Disney that autumn.
Sky's 40% share in Nickelodeon UK Ltd. is managed by a Sky UK subsidiary named Kidsprog Ltd. which was established in 1992 as a holding company for Sky's investment in Nickelodeon UK, back then BSkyB (British Sky Broadcasting) owned a 50% share in Nickelodeon UK, this was reduced to 40% during the business year of 30th June 2005-30th June 2006 following the issue of more share capital, therefore increasing Viacom's stake.
At present, The Head of Sky's children's division, Lucy Murphy sits on Nickelodeon UK's board, as well as Mark Winterbottom, Director of Sky Channel Distribution, they sit on the board alongside Jules Borkent, VP of Programming at Nickelodeon International, Maria Kyriacou, President of ViacomCBS Networks International (UK and Australia), and Sarah Rose, Chief Operating and Commercial Officer at ViacomCBS UK.
Currently, select DreamWorks programs air on Sky Showcase on Sunday mornings.