Labour has "run out of excuses" to oppose an early election, Boris Johnson has said, as MPs vote on whether to back his call for a December poll.
The PM said "nobody relished" going to the polls weeks before Christmas but this Parliament had "run its course" and was "incapable" of settling Brexit.
The PM has formally accepted the EU's offer of a Brexit extension until 31 January 2020 agreed earlier on Monday.
In a letter to EU officials, he said it was an "unwanted prolongation".
Urging the EU to rule out any further extension, he said there was time to ratify his Brexit deal but he feared the current Parliament would never do so "as long as it has the option of further delay".
The PM's acceptance means that the UK will not leave the EU on Thursday - despite a "do or die" promise he repeatedly made during this summer's Tory leadership campaign and since taking office in July.