LONDON (Reuters) - British voters have shifted toward voting to leave the European Union in next month's referendum according to two surveys by polling firm ICM published on Tuesday, surprising investors and sending sterling sharply lower.
A telephone poll for the Guardian newspaper showed 45 percent of respondents favored leaving the EU compared with 42 percent who said they would vote to stay in the bloc.
Telephone polls have tended to give the Remain campaign a comfortable lead over those wanting to vote to leave the 28-member bloc. A previous ICM telephone poll published on May 16 showed the Remain side holding an eight percentage-point lead.
ICM said the telephone poll was their first phone poll to put the Leave campaign in the lead.
Online polls have largely suggested a tighter race but a weekly online poll by ICM - separate to its phone survey - which was also published on Tuesday showed voters favored Britain leaving the EU by 47 percent to 44 percent.
Last week's online ICM poll put the two camps neck and neck at 45 percent each.
Sterling fell after the poll was published and lost more than a cent against the dollar. British government bond prices, which investors buy to counter risk, rose to a session high.
The polls were conducted between May 27 and 29. The telephone poll interviewed 1,004 people aged over 18 while 2,052 people took part in the online survey, ICM said.
(Reporting by Kate Holton and William Schomberg; editing by Stephen Addison)