0102 GMT May 25, 2019
A opinion poll published on Friday shows that May's lead has shrunk to five points from 15 points two weeks ago.
The Ipsos MORI poll also shows that the Conservatives’ share of the vote has decreased to 45 percent.
Four similar surveys were released in May with one showing the gap between the two parties halving to nine points.
Although previous polls conducted in the early stages of campaigning indicated that May was on course for a landslide with a majority of up to 150 seats, the new polls depicted rather a bleak prospect for the Conservatives.
Meanwhile, the YouGov poll released on Thursday showed that Corbyn is now London's favorite candidate for the British prime minister as his party has opened a 17-point lead over the ruling Conservatives in the capital.
The poll sees Corbyn overtake May as the preferred choice to lead the country among Londoners.
Corbyn argues that May’s policy plans would create "war between generations."
“Where the Tories look to divide, Labour seeks to bring people together,” Corbyn said in May. “The Tories are now trying to pitch the young against the old.”
This is a remarkable change in fortunes for Labour, which was 24 points behind the ruling party when the snap general election was called in April by May. The general election will be held on June 8.
Such a result on June 9 would be catastrophic for May who has argued that the UK needed certainty, stability and strong leadership in Brexit negotiations with the EU.
Failure to win with a large majority would weaken May in the Brexit talks and a majority loss in parliament would throw British politics into turmoil.