Every so often I look at the numbers around the last election and it just blows my mind.

There are 45 historically attainable seats for Labour where the Tories have a majority more than twice as large as their national vote lead.

If you wonder why Keir Starmer is desperately trying to play safe until he's prepared to show his hand, it's because he knows how hard it will be to win.

Labour didn't just lose 2019 by a shed tone of votes nationally, it's vote evaporated in marginal and former safe seats.

Let's look at some excellent examples where the last time Labour won in 2005 they were in a great position, and in a 15 year period they've totally squandered their position.

Former safe-ish Labour seats that are now incredibly safe for the Tories. Mostly in the Midlands.
#Mansfield best example.
2005: Con 18 vs Lab 48 = Lab maj of 30%
2019: Con 64 vs Lab 31 = Con maj of 33%
(31.5% swing in 14 years)

Other examples include Walsall North, Sherwood, Plymouth Moor View, Stock-on-Trent South.
#CannockChase is another worthy example:
2005: Con 30 vs Lab 51 = Lab maj of 21%
2019: Con 68 vs Lab 25= Con maj of 43%
(32% swing in 14 years)

There's another set of seats that are also worthwhile looking at. Seats that naturally lean Labour in a closer contest but now are ridiculously safe Conservative seats. There's more than a dozen of these

My preferred example is #Dartford:
2005: Con 41 vs Lab 43 = Lab maj of 2%
2019: Con 63 vs Lab 28= Con maj of 35%
(18.5% swing in 14 years)

My preferred example is #Harlow:
2005: Con 41.2 vs Lab 41.4 = Lab maj of 0.2%
2019: Con 64 vs Lab 31= Con maj of 33%
(16.5% swing)

These are interesting because they are a bit more widely spread, but actually are pretty prominent in the South. if you extend the definition slightly to formally marginal Tory seats that should easily be in reach of Labour, most of them are southern seats.

Hemel Hemsptead, loads of the Kent seats such as Gillingham, Rochester etc. All seats that in 2005 had thin Tory leads and safely Tory.
E.g. #Sittinghabourne:
2005: Con 41.7 vs Lab 41.7 = notionally tied
2019: Con 68 vs Lab 20= Con maj of 48%
(24% swing)

For context, the national swing in England between 2005 and 2019 is only 6.8%. So those movements are huge.

Starmer must be painfully aware that the basics of the Tony Blair parliamentary majorities in the South and Midlands are now solidly Tory territory.

He's trying to do that hard work of regaining trust. But you do look at some of the numbers and assume that he really is unlikely to win these back in a single parliament.