The pint of milk is "not at all at risk" from legislation going before MEPs on Thursday, a spokesman for the European Parliament in London has said.
There are 568 millilitres in a traditional bottle of milk
The British Retail Consortium has said the legislation would allow milk to be sold in a range of metric quantities, confusing consumers used to pints.
But the spokesman, Simon Duffin, said an amendment - passed at committee stage - would protect Britain's pint.
"It's pretty clear that pints can be sold and will carry on being sold."
On Thursday, MEPs will vote on legislation to standardise quantities of pre-packaged products.
The British Retail Consortium (BRC) said: "If the legislation goes ahead, this will cause confusion amongst consumers, because as long as milk is sold in millilitres or litres, there will be no specific measurements required by law.
"For example, one retailer could sell milk in 500ml, another at 525ml and another at 564ml (roughly the equivalent of a pint)."
Speaking on BBC News 24, the BRC's director of food and consumer policy, Andrew Opie, said:
"I just think the pint of milk is just one of those iconic things that everybody in the UK understands what a pint of milk is and uses it shorthand really for milk."
Mr Duffin said the amendment to allow the pint to continue in Britain was unlikely to fail in the European Parliament.
The parliament's Internal Market and Consumer Protection committee commissioned the report amending the legislation.
The report recommends that milk should be packaged in seven different metric sizes so that shoppers know exactly what they are buying.
But it adds that imperial units such as pints should be allowed to continue.
"Consumers habitually buy certain sizes. If ranges were liberalised, distributors could try to undercut each other by reducing each size in order to make a slightly bigger profit," the report says.
Mr Duffin said almost all the parties in the European Parliament were backing the amendment and accused the consortium of using scare tactics.
"We don't see any particular reason for the BRC putting out their press statement."
But Mr Opie told Radio Five Live there was still a threat.
"The vote that's going to be taken on Thursday has a number of amendments - some of which are very positive... but there is still a threat to the British pint if the amendments that we want aren't voted for.
"All we're pointing out is the work that we're doing. We're writing to MEPs, we're working with UK MEPs, to make sure the vote goes the right way.
"So what we're telling people is 'there is a vote on this issue, it could go the wrong way, but we're hopeful from all the work that everybody's putting in that it will go the right way'."