The call comes as MPs are set to debate amendments to the Environment Bill in Parliament (during its report stage) later today.
An amendment calling for legally binding plastics reduction targets to be included in the bill has been tabled by Conservative MP Chris Loder (West Dorset).
In their letter to Boris Johnson the group says that while government initiatives - such as the ban on plastic straws, stirrers and cotton buds – have had positive impacts, a more over-arching approach is needed to deal with the problem.
In particular, the Prime Minister is being urged to ensure that long-term and interim targets for cutting plastic pollution are included in the government's flagship Environment Bill, which is currently passing through Parliament.
As well as Caroline Lucas, signatories to the letter include businesses such as Iceland and Neal's Yard, MPs, faith leaders, academics and organisations such as Friends of the Earth, the WI, Surfers against Sewage, Keep Britain Tidy, City to Sea and Tearfund.
Friends of the Earth plastic campaigner Camilla Zerr said:
"Despite the introduction of a few welcome measures, the government must go much further to stem the rising tide of plastic pollution pouring into our environment.
"Boris Johnson has a golden opportunity to get to grips with the crisis by ensuring that the Environment Bill contains legally-binding targets for reducing the amount of plastic waste polluting our planet every year
"The government has promised to be a world leader on the environment and set a gold standard for cutting down on plastic waste. Now it's time to deliver."
Although the government's focus has rightly been on the coronavirus crisis over the past year, the plastic pollution problem has not gone away – and appears to have been exacerbated by the pandemic, with disposable face masks found on more than two thirds of recent Marine Conservation Society beach clean ups.