British Prime Minister Theresa May's lead over the opposition Labour Party dropped to 6 percentage points in a poll published on Tuesday, the latest to show a tightening race since the Manchester bombing and a U-turn over social care plans.

Barely two weeks ago, a series of surveys showed May was on course for a landslide parliamentary majority in a June 8 snap election which she called to secure a strong mandate for Brexit talks.

But her Conservative Party remained on 43 percent according to a survey conducted by Survation for ITV's Good Morning Britain program, seeing their lead drop as support for Labour rose 3 percentage points to 37 percent.

The poll was conducted on May 26 and May 27 in the aftermath of a suicide bombing which killed 22 people in Manchester last Monday and following a government U-turn on unpopular proposals to make elderly people pay more towards their care.

Questions continue to mount over how much Britain knew about Salman Abedi, responsible for the deadliest militant attack on British soil for 12 years. May was interior minister from 2010 to 2016.

Just over half of the 1,009 respondents said May would make the best prime minister, whilst support for Labour's Jeremy Corbyn stood at just 30 percent, albeit higher than in previous surveys.