There are millions upon millions of people in this country who have little or no loyalty to Britain and a fair number who are actively hostile to it. The idea you could just conscript them and send them off to war without mass violence and insurrection is laughable. That's mostly people of immigrant stock who have their first loyalty to other countries, but not just them. How's it going to go trying to conscript Celtic's "green brigade" into the British army? Or scousers who can't abide the national anthem?
In the world of equality, we can't be seen to treat men and women differently or indeed to acknowledge any difference between them. So we'd be conscripting young men and women on an equal basis. Even amongst the general population who do have a loyalty to Britain, do you think people would just stand back and watch young mothers and daughters conscripted off to war?
We've got a whole generation , probably 2 or 3 generations who've been brought up in a culture where hurty words are considered as bad if not worse than actual violence, who've never faced any kind of discipline and who very much "know their rights". They've also been brought up on to believe that Britain and it's history and culture is something to be ashamed of. The idea you could shape them into some sort of fighting force to take the fight to Russia across to protect their country seems delusional.
The whole idea is laughable.
Conscription could simply never work in modern Britain in any conceivable circumstances. I'm sure in a war that posed a genuine threat to the continuity of the nation there'd still be plenty of volunteers, mainly the kind of folk who are ridiculed as " Gammon" but any attempt at conscription would result in mass rebellion, the downfall of the government and hasten the victory of whichever enemy they'd managed to conjure up.