Samantha Cameron visited Syrian refugees in Lebanon in March and is cited as the "biggest explanation" for the Prime Minister's stance over the conflict.
Sources close to Mr Cameron confirmed to the paper that his wife had pushed for a more robust response to the humanitarian crisis.
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After a sweltering day, where temperatures reached a record high for July, the weather turned.
One of Britain's leading tour operators, Thomas Cook, has joined a growing push for changes to the way tourists receive security warnings.
Thunderstorms affect mostly southeast England on Thursday with a mixture of sunny spells and showers into the afternoon.