The government suggests a second referendum on Brexit would take up to a year to organise, in a document seen by ITV News.
The government has handed out the one-page memo - setting out how a new people's vote would be organised - to MPs involved in Brexit talks.
Passage of primary legislation would take around seven months, while Electoral Commission testing of the question would require 12 weeks, the document says.
Theresa May's government has consistently ruled out holding a second referendum on membership of the EU.
Sight of the document comes just days the prime minister's Brexit deal suffered a historic defeat in Parliament.
Meanwhile, Jeremy Corbyn has encouraged Labour MPs not to engage with the government until a no-deal Brexit is taken off of the table.