Britain's Prime Minister Theresa May works on her campaign bus as it travels through Staffordshire. REUTERS/Ben Stansall/Pool

LONDON (Reuters) - British Prime Minister Theresa May is on track to win a 64-seat majority in Thursday’s national election, a model by businessman and former Conservative Party donor Michael Ashcroft showed on Tuesday.

Ashcroft, who has funded a significant amount of opinion polling in recent years, said his model now pointed to a greater majority for May’s Conservatives than it had on June 2, when it indicated a majority of 60.

“As always, it is important to emphasize that the Ashcroft Model deals with probabilities not predictions, meaning the actual result may well fall either side of these estimates,” Ashcroft said, adding that model results were sensitive to assumptions about which groups of voters turned out.