Britain's Prime Minister Theresa May speaks at an election campaign event at Pride Park Stadium in Derby, Britain June 1, 2017. REUTERS/Stefan Wermuth

LONDON (Reuters) - British Prime Minister Theresa May’s lead over the opposition Labour party has shrunk to five points from 15 points just over two weeks ago, an opinion poll from Ipsos MORI showed on Friday.

With less than a week to go before the national election, the poll showed the Conservatives’ share of the vote had fallen to 45 percent, down four percentage points since the previous poll published on May 18.

Labour’s share of the vote increased six points to 40 percent, according to the poll which was published by the London Evening Standard newspaper.

The poll is the latest to show a narrowing lead for May. A YouGov opinion poll on Wednesday showed the Conservatives’ lead had fallen to a fresh low of 3 points.

A failure to win the election with a large majority would weaken May just as formal Brexit talks are due to begin, while the loss of her majority in parliament would pitch British politics into turmoil.