May has seen her once-commanding lead over the Labour Partyand its veteran hard-left leader Jeremy Corbyn narrow sharplysince she surprised almost everyone by calling a snap electionin April.
Of six polls published on Wednesday, two showed theConservatives widening their lead over Labour, two showed anarrowing and two were unchanged.
But they mostly suggested she would increase the smallmajority she inherited from David Cameron last year, shortlyafter the surprise referendum decision to take Britain out ofthe European Union.
Polling firm ICM said Conservatives' wide lead of 46 percentto 34 percent for Labour would give May a majority of 96 seats,up sharply from the working majority of 17 she has had until nowand bigger than any Conservative majority since the days whenMargaret Thatcher was prime minister.
The Independent newspaper said the 44-34 lead for theConservatives in a poll it commissioned from ComRes would giveMay a majority of 74.
YouGov, which found the Conservatives' lead had increased toseven percentage points from four during the weekend, also saidMay would bolster her power in parliament.
"The seven-point Conservative lead is the same as at theprevious election, but we think it is likely they willnevertheless be returned with an increased majority," YouGovDirector Anthony Wells said.
The polls were conducted after a deadly attack by Islamistmilitants in London on Saturday.
ICM and ComRes have tended to give the Conservatives biggerleads than other polling firms.
At the other end of spectrum, Survation said theConservatives' lead stood at just one percentage point, echoingtwo polls it published in recent days which called into questionwhether May would get a majority at all.
Polling experts have said the main difference between thepolls which give the Conservatives a big lead and ones such asSurvation which suggest a tighter race is largely down tovarying estimates of how many young voters, who typicallysupport Labour, are likely to actually vote on Thursday.
Investors took the latest findings as a sign May was likelyto emerge victorious, giving her a boost before the start ofBrexit talks this month. Sterling rose by nearly half acent against the US dollar after the ICM poll was published.
GAMBLE
ComRes Chairman Andrew Hawkins said May was in the clearafter securing the support of around 2 million voters - worthabout six percentage points in the polls - who backed theanti-EU UK Independence Party in Britain's last election in2015, and who have warmed to her tough stance on negotiatingBrexit.
"Despite Mrs May's ratings taking a hit during the campaign,older voters in particular have stuck with her party and itappears that the electoral gamble is about to pay off," he saidin a blog.
The big differences in the poll findings in the run-up toThursday's vote have added to scepticism among critics ofpolling who point to how the industry largely failed toaccurately predict the outcome of the 2015 election and lastyear's referendum vote to exit the EU.
