Opposition gains in British polls, but May's party keeps strong lead

By Alistair Smout and William JamesLONDON (Reuters) - Three opinion polls showed a rise in support for Britain's opposition Labour Party, although Prime Minister Theresa May's Conservatives maintained a commanding lead ahead of a June 8 election expected to define the terms of the country's EU exit.The polls published late on Saturday showed May's Conservatives remained between 11 and 17 points ahead of Labour - still enough to deliver a clear victory as she seeks a mandate for her plan to imple