Polls have opened across Scotland in a referendum that will decide whether the country leaves its 307-year-old union with England and becomes an independent state.

More than 2,600 polling places will be open Thursday from 7 a.m. (0600GMT, 2 a.m. EDT) until 10 p.m. (2100GMT, 5 p.m. EDT).

Turnout is expected to be high, with more than 4.2 million people registered to vote — 97 percent of those eligible.

Polls suggest the result is too close to call, with the pro-independence Yes side gaining momentum in the final weeks of campaigning.

First Minister Alex Salmond is casting his vote near his home in northeast Scotland.

If the Yes side prevails he will realize a long-held dream of leading his country to independence after an alliance with England formed in 1707.