Welsh centre Jamie Roberts - facing Australia for the first time this summer due to injury - has scored the Lions' fourth try, taking a pass from replacement Conor Murray before galloping home.
Halfpenny makes it another seven points, and the Lions start to celebrate a series win.
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The four candidates who want to lead the Labour party have visited Cardiff trying to persuade party members for support.
Australia's first female PM Julia Gillard has told ITV News Wales about sexist barriers in politics and her affinity to her native Wales.
Many eastern areas will see a fine morning with spells of sunshine, but showers will spread from the west by the afternoon.