Plastic straws and cotton buds could be banned in England as part of the government's bid to cut plastic waste.
Announcing a consultation on a possible ban ministers said 8.5bn plastic straws were thrown away in the UK every year.
The prime minister said plastic waste was "one of the greatest environmental challenges facing the world", writes BBC
And Theresa May will urge leaders at the Commonwealth Heads of Government Meeting, which starts later, to follow the UK's lead in tackling the problem.
The Queen will formally open the summit at an event at Buckingham Palace attended by prime ministers and presidents from the 53 states that make up the organisation.
Mrs May claimed the UK was a "world leader" on tackling plastic waste, highlighting the charges that have been introduced for plastic bags, the ban on microbeads and the announcement in March of a consultation on introducing a deposit return scheme for drinks containers in England.
"Alongside our domestic action, this week we are rallying Commonwealth countries to join us in the fight against marine plastics," she said.
"The Commonwealth is a unique organisation, with a huge diversity of wildlife, environments and coastlines.
"Together we can effect real change so that future generations can enjoy a natural environment that is healthier than we currently find it."
The environment secretary Michael Gove describes plastic waste as a worldwide emergency, which naturally raises questions about the speed of the government's response.
The headlines talk of a ban on plastic straws - but the announcement is about a consultation to do that. A similar exercise is under way about a deposit scheme for plastic drinks bottles, and MPs were not impressed on Wednesday when they learned that the system itself will not come into effect until 2020.
When ministers talk of the UK leading the world on this hot topic it's worth casting an eye over the actions of other countries. Dozens have actually banned plastic bags - Britain has a system of retailers having to charge for them.
And since last year Kenya has adopted the most draconian measures of all: there are fines if you use a plastic bag and if business people are caught making or importing them, they actually face up to four years in jail.
Amid many claims about fighting a war on plastic, the Kenyans are leading the charge.