7 constituencies that could tell you who will win the general election (and what time they will declare)

The days of Labour-Tory dominance and uniform national swing are over - but the results of some seats could tell you who is on course for victory

To say that this week's election is the "most unpredictable for a generation" has become a cliche.

Although most constituencies remain safe, the era of two-party dominance and uniform national swing has given way to a much more complicated, multi-party picture of three-way marginals and ultra-local campaigns.

But some constituencies will give a good indication of who is doing well, and who is doing badly. Here are seven.

Lancaster and Fleetwood (Conservative)

Main challenger: Labour

Swing needed: 0.8%

Can the Tories hold on in the North? A key Labour target seat and one they must take to be on course for victory.

What time we'll know: 3am

Derby North (Labour)

Main challenger: Conservative

Swing needed: 1.4%

Used to be safe Labour but the Tories came close to claiming the seat in 2010. It will be very bad news indeed for Ed Miliband if he can't hold on here.

What time we'll know: 4am

Southampton Itchen (Labour)

Main challenger: Conservative

Swing needed: 0.4%

Labour's John Denham, a former cabinet minister, is standing down and this key Tory target represents a significant test of well Labour is doing in the south.

What time we'll know: 4am

Thurrock (Conservative)

Main challengers: UKIP and Labour

Swing needed: 29.4% Con to UKIP, 0.2% Con to Lab

A key three-way marginal held by Tory Jackie Doyle-Price by just 92 votes from Labour back in 2010. Ashcroft polls have put UKIP in the lead.

What time we'll know: 3.30am

Great Grimsby (Labour)

Main challengers: UKIP and Conservative

Swing needed: 2.2% Lab to Con, 26.5% Lab to UKIP

Another three-way marginal thanks to the UKIP surge. Veteran Eurosceptic Austin Mitchell is standing down; UKIP fancies its chances but the Tories came close in 2010.

What time we'll know: 3am

Inverness, Nairn, Badenoch and Strathspey (Liberal Democrat)

Main challenger: SNP

Swing needed: 22%

Could Danny Alexander become one of the most high-profile victims of the SNP surge? The polls suggest as much. Labour was second here in 2010.

What time we'll know: 4am

St Austell and Newquay (Liberal Democrat)

Main challenger: Conservative.

Swing needed: 2.8%

A key test of whether the Lib Dems can hold off the Tory challenge in the South West.

What time we'll know: 6am