Britain's Dec. 12 election could well result in another parliament where no party commands a majority, Prime Minister Boris Johnson's top advisor Dominic Cummings said on Wednesday.

Johnson's Conservative Party holds a sizeable lead over the opposition Labour Party in opinion polls, although the gap has narrowed this week.

"Trust me, as someone who has worked on lots of campaigns, things are MUCH tighter than they seem and there is a very real possibility of a hung parliament," Cummings wrote on his blog.