1 Police Officer: 'Ello 'ello 'ello, what's all this then?
2 Student: These people are Nazi spies!
3 Police Officer: That's a jolly rum thing, then. Righto, me lovelies, you're nicked! You lot are 'ereby under arrest for spying!
4 Mercutio: I almost feel like I want to say, "It's a fair cop."

I suspect that British police have training in speaking like this.

[two minutes of Googling later...]

Actually, it appears that nowadays British police have training in not speaking like this.