Couriers in London stormed a Royal Mail building as part of a strike to demand workers' rights including holiday pay and pensions
Nearly 100 gathered in Whitechapel outside the headquarters of eCourier which is owned by Royal Mail.
The work of these drivers includes medical items such as blood and other medical specimens.
"So when your loved one has a major haemorrhage in a hospital, these guys are responsible for asking bags of bloods to keep them alive. Quite often, these guys are making less than minimum wage when doing that job," explained Alex Marshall, president of the Independent Workers Union of Great Britain.
"What we're arguing is just like Uber drivers, Bolt drivers, recently, they should be getting holiday pay and pensions.
"Some of these guys have been working for eCourier for over a decade, and for that whole time they've never been given holiday pay for that whole time they've never been given a pay rise, so their pay has essentially gone down."
The protestors demands include compensation in the form of back-dated holiday pay, union recognition, a pay package of £20-an-hour plus mileage.
They say they currently have to cover all of their travel costs, such as upkeeping their bikes and paying for new ones when needed with the union also saying some of the workers take less than the minimum wage annually after they have covered their travel costs.
One of the couriers, spoke of her experience saying: "There is a very toxic environment, sometimes we have people who call us up and say 'you have to do this work,' when I say I'm on my lunch break, they say 'I tell you when you can stop'.
The protestors were joined by supporters including an A&E doctor from Newham Hospital.
He said: "Couriers who provide this essential service, they are key workers for the NHS and for our country are treated abysmally by their sub contractor as well as NHS employees.
"I'm here to support them in their fight for fair pay, dignity and respect in the workplace."
Kay Ballard from Unite, Tower Hamlets, added: "They're asking for dignity, and wages that are owed [to] them.
"These eCouriers literally shift medical, they keep hospitals going, they're keeping every one of us alive....would these managers work with these wages? On these terms and conditions?"
An eCourier spokesperson said: “We would like to reassure customers that we have robust contingency plans in place to cover the small number of couriers taking industrial action and we are confident that there will be no impact on services.
“We haven’t had any complaints or claims from individual drivers that support IWGB’s position or the allegations made. eCourier offers couriers the choice of being engaged either as workers (with entitlement to rights such as holiday pay and sick pay) or as self-employed contractors, and notes that most have preferred to engage via the independent contractor arrangement. We are currently in the process of reminding eligible couriers of the option to engage as workers.”
