No 10 source says a second letter makes clear Boris Johnson believes an extension would be a mistake.
The government has lost a vote on its Brexit deal, compelling it to seek a delay from Brussels.
Find out if your MP voted for a proposal to withhold Commons approval to the Brexit deal until it becomes law.
Supporters of the "People's Vote" cheered as MPs voted to withhold approval of the PM's deal.
The party helped pass the amendment that could delay Brexit until all necessary laws are passed in Parliament.