Heartbroken staff and volunteers at Sandal Library were left devastated after a community dementia garden was hit by vandals for the third time in four months.
They said vandals broke the summer house, threw paint over plants, damaged seating and a wooden archway and damaged plants in the most recent "horrendous" attack.
And Wakefield South councillor Monica Graham says urgent action will now be taken to ramp up security at the site.
She said: “I was shocked and disgusted at what I saw. I had immediate discussions with the council and temporary security lighting and cameras will be installed very quickly. We will then sort out funding for permanent security systems.
“This vandalism has to be stopped in its tracks. It is devastating for staff and volunteers who have put so much effort into producing something so worthwhile for the community.”
The official opening of the community garden, called 'Memory Lane' was scheduled for July 28 and 29. But this may now have to be postponed.
Les Goddard, chairman of Sandal Community Association which has provided a bench for the garden, said: “This vandalism is utterly mindless. I just can’t understand the mentality of someone who would do this.”
The Friends of Sandal Library spent nearly a year raising £10,000 to fund the garden, for people with dementia and their families and carers.
Volunteers have spent hours of their time landscaping the site, creating vegetable plots, planters and putting in place a shed and grassed area.
Their efforts were first thwarted by vandals early in March, when newly-planted bulbs were torn up and stolen.
But volunteers did not give up, and set about re-planting.
Just weeks later, at the end of March, the garden was trashed for a second time.
Planters and furniture was overturned, gravel was scattered around the site and fast-food litter was dropped on the floor.
The most recent vandalism occurred on the week beginning June 19.
Coun Jacquie Speight, Wakefield Council's cabinet member for culture, leisure and sport, said: “It is so very disappointing that there has been yet more vandalism in the garden.
“Sandal was the first library in the community to be recognised as dementia friendly.
"The main reason the garden was created was so that people with dementia and their carers have a place to reminisce and to take part in activities.
"It is bewildering as to why anyone would want to spoil the hard work of the Friends group and the volunteers.
“I would urge anyone who has any information about this to report it to the police.”
Sandal Library was refurbished with help from The Alzheimer’s Society in 2015 to make it easier for people living with dementia to use.
Anyone with information about the vandalism is asked to contact the police on 101.