If you’re looking for a litmus test for the national political mood, look no further than Lancashire.
Labour-controlled for 28 years, the county was painted blue in 2009, leaving the Conservative Party with a 34-seat majority and Labour heading for General Election defeat.
Ed Miliband is desperate to get it back, evidenced by his numerous visits to the county in recent weeks. He knows anything other than overall Labour control come Friday morning will be interpreted as a vote of no confidence in his leadership.
David Cameron knows that, and he also knows that a Tory hold will be a huge boost for both him personally, and his grassroots activists.
Historically, Labour has held the keys to county hall, but it is wrong to assume, as many do, that Lancashire itself is a natural Labour stronghold - a point those close to Mr Miliband were keen to point out to me during a visit to Cleveleys on Monday.
It’s the Tories who hold nine of the county’s 16 parliamentary seats; Labour holds just six. Areas like Fylde, the Ribble Valley and Wyre are as blue as they get. It was the size of David Cameron’s victory that surprised last time out, not the victory itself.
Both parties have a base to build from in one of Britain’s biggest counties, but both have a history, locally and nationally, of fighting fiercely over a handful of seats. Lancashire represents a county with one of the highest concentrations of marginal Westminster constituencies; half of MPs here have fewer than a 4,000-vote majority; half of those have fewer than 2,000. On Thursday those MPs will be examining the results with a fine-tooth comb.
So lots of voters to persuade, in a place where voters have a history of being persuaded.
A litmus test Lancashire certainly is, but a guaranteed key to government it is not. Labour controlled county hall in Preston during nine of Margaret Thatcher’s 11-year reign, and for all of John Major’s, winning four county council elections in the same period - yet it lost three General Elections.
Equally, what followed an emphatic Tory win here in 2009, in which the party gained 20 seats and 42% of the vote, was not a 2010 Cameron-Conservative coronation but a still-unconvinced electorate and a coalition government. Voters had simply used a local election to kick an old-looking New Labour. A year later, the kick wasn’t so hard, and Cameron didn’t look so appealing.
What those elections do show - though - is Lancastrians have a history of punishing the government of the day.
Labour certainly has a lot of ground to recover to ensure that punishment once again delivers a truly Red Rose county on Friday. The Conservatives will see hanging on by the skin of their teeth as big a victory. Yet deep down David Cameron knows that as the sitting Prime Minister, he can explain away defeat much easier than the Labour leader can, especially in Lancashire.