Go on, then
What it really means
The happy sound of resistance collapsing: it means "yes please" after a token refusal. Most often heard when someone is offered tea, cake or one more drink.
Context, tips & common mistakes
"Go on then" is the sound of a Brit accepting something they just declined — the final move of the offer dance: "Cuppa?" "No, I'm fine." "Sure? Pot's fresh." "...Go on then." The first refusal was politeness, not preference; the re-offer gave permission; "go on then" accepts with a pantomime of being persuaded, keeping the accepter's modesty intact.
Two practical lessons live in this. As host, offer twice: a first 'no thanks' to tea, cake or seconds may be ritual, and one gentle "are you sure?" is expected — though a second refusal is final and pressing further is rude. As guest, you now hold the native's tool for accepting treats gracefully; deliver it with a small sigh of surrender for full effect.
Example conversation
What you could say back
No spoken reply needed for this one.