Frozen brakes ?

[Classic Chim]

Hi chaps
Today at 6 am I decided rather foolishly to drive the Tvr to work, 3 inches of snow lay on the car, wasn’t until I’m on the road do I realise I’ve got what felt like no servo assistance, very firm brake pedal and no brakes unless I put 80 psi in via my foot!!! Ran my foot on said pedal to try and warm the brakes as I couldn’t be sure what it was but it made no difference, then left the car in the sun during the day.
Brakes working fine when I drove home.
So what the heck was that.
Can anyone think of what could cause this, I have DOT 5.1 brake fluid and Brembo 4 pot brakes.
The pedal felt exactly the same as when there’s no servo as in when using brakes with engine off
How would the cold effect the servo assistance.

Cars parked up now until the snow goes

[blaze_away]

Could be damp in servo valve frozen shut during the night then thawed out during the day as it warmed up.

[Classic Chim]

Need to check my clutch fluid level so better have a good look see at the servo.
Probably - 5/7 degrees so that might have something to do with it.

[QBee]

Not related directly, but my daughter complained her lpg cooker wasn’t working the other evening. Ice in the regulator on top of the cylinder, I guessed. Warm water poured over it, I heard the gas whooshing out and down the pipe to the hob as soon as it melted the ice inside the regulator

[Classic Chim]

The cars slowly thoring out so I’ll check later.
Clearly cold related.

[Classic Chim]

Ran car today after 4 days of it being frozen solid.
Brakes working with there usual level of refinement.
Only 4 days away yet driving today, wow what cars.