David Cameron said he has told Google: You can map the world from space so do more to stop people searching for child abuse images.
If not, the Prime Minister said, the Government will legislate.
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Labour have lost the Copeland by-election, a seat they had held since 1983, as the Conservatives edged the vote by 2,000 votes.
Labour have held onto the crucial seat of Stoke-on-Trent, brushing aside UKIP leader Paul Nuttall in the process.
A highly toxic chemical was used in the death of North Korean leader Kim Jong-un's half brother last week, tests have shown.