Britain's Prime Minister Boris Johnson leaves the Conservative Party headquarters in London, Britain November 4, 2019. REUTERS/Peter Nicholls

LONDON (Reuters) - British Prime Minister Boris Johnson’s Conservatives have a seven percentage-point lead over the opposition Labour Party ahead of a Dec. 12 election, according to an ICM poll published by Reuters on Monday.

ICM’s first poll of the election campaign put the Conservatives on 38% and Labour on 31%. The pro-European Union Liberal Democrats had the support of 15% of those surveyed, while the Brexit Party was on 9%.

The poll of 2,047 people, carried out online between Nov. 1 and 4, shows a narrower gap than recent surveys from other pollsters, which have put the Conservatives between 8 and 17 percentage points ahead of Labour.

ICM said the survey showed the two main parties losing a similar proportion of voters over Brexit.

It said 11% of those voted Conservative at the last election in 2017 were now planning to vote for the Brexit Party, while 12% of those who backed Labour in 2017 intended to vote for the Liberal Democrats.

More than two-thirds of those who voted ‘Remain’ in the Brexit referendum in 2016 and for the Conservatives in 2017 intended to stick with Johnson’s Conservatives, ICM said.