Celebrations have been going on through out the weekend to mark 125 years of Port Sunlight.
The site in Wirral was the brainchild of soap magnate Lord Lever.
He set up a factory surrounded by a village for his employees and their families.
At it's height there were 8,000 workers at the site.
The plant expanded to produce some of the worlds biggest brands including PG Tips and Persil.
VIDEO CLIP: Katherine Lynch, Museum Manager, Port Sunlight Village Trust
VIDEO CLIP: Gavin Hunter, former Unilever employee
Unite, which represents some Unilever staff, says it is assessing the impact of today's Unilever announcement.
The firm said it is planning to close plants in Wales and Slough - but invest £40m at its Port Sunlight factory on the Wirral.
Unilever said its plans would "transform" Port Sunlight into a "significant centre of excellence" for the manufacture of shampoo and shower gel products, with growth potential for the next decade.
Unilver says the £40m investment plans for Port Sunlight would create 150 new jobs.
Transfers would increase workforce from 1,500 to 2,000.
Unilever has announced it's investing £40m in its biggest factory in Port Sunlight, Wirral, while shutting sites in Swansea, Bridgend and Slough with the loss of around 800 jobs.
The company makes household brands like Persil, Dove and Flora.