Customers are complaining that certain tins of B&Q paint are not sturdy enough and can open in the car on the way home.
The problem is coming from the paint mixed by B&Q staff after customers request a unique colour. The Valspar-branded paint is placed into flimsy plastic containers that bends so easily that the lid can pop off.
Speaking to The Guardian, Kelly and Steve O'Reilly explained that the paint had caused £9,000-worth of damage after opening in the boot of their new BMW.
"When we looked at the tin we couldn't believe how flimsy it was. A 49p milk carton has more protection against spillages than these. They are patently not up to the job of carrying paint," Kelly said.
Another couple explained how their 2011 Mercedes-Benz has just been written off by their insurer after a tin of paint left in the rear foot well opened during the trip home from the store.
B&Q says that once the paint has left its store it's no longer responsible for it. However, it has paid out to some customers as a gesture of goodwill, but has fought others through its lawyers.
Customers who haven't been reimbursed have faced claiming through their own insurance, leading to increased premiums.
A statement from B&Q says: "All the products we sell at B&Q are rigorously tested before we put them on sale. In the past year more than three million cans of Valspar store-mixed paint have been bought in our stores, with fewer than one in 100,000 tins leading to a paint spillage complaint.
"On the rare occasion that a customer experiences a problem, we take this seriously and assess the complaint to understand what happened and whether anything could have been done differently. All paint containers used by Valspar meet industry standards and their supplier is accredited to ISO 9001:2015. Despite this, we are carrying out additional testing so that we can remain completely satisfied that the cans are fit for purpose."