Will this be the largest ever drop for a governing party?

According to the average of the public polls, Labour is going to have a results in the mid to high 20s, which means their drop off in support (in absolute terms) will be between 21% and 25%.

I was curious as to whether this would one the largest ever drop in support for a governing party, so I looked it up.

As you can see the likely drop in support for Labour is unprecedented. Even disastrous elections such aa 1990 only saw a 12% drop in support and in 2023 Labour may drop twice that.