Complex sentence: During the campaign, Margaret Thatcher, against whom he demonstrated as a student 17 years earlier, came to Colchester to support his attempt to win the seat for the Conservatives, but he came in a close second to the Liberal Democrat Bob Russell.
Split into simpler sentences: During the campaign, Margaret Thatcher, against whom he demonstrated as a student 17 years earlier, came to Colchester to support his attempt to win the seat for the Conservatives. But he came in a close second to the Liberal Democrat Bob Russell.