How likely is a UPS workers strike and how would it affect shipping?

Negotiations between the US's largest shipping company and its union have stalled less than a month before the contract expires - here's what we know

Time is running out for negotiations to avert the largest strike against a single employer in US history. Contract negotiations between UPS, the largest shipping company in the US, and its workers' union have stalled less than a month before the union contract expires on 31 July. Without a contract, the union said that its 340,000 full- and part-time workers will strike, something that would significantly disrupt the US economy.

Here's what we know so far about negotiations and the potential strike: