Two people are being questioned about the kidnapping of a British photographer in Syria.
The man and woman were arrested at Heathrow Airport. Scotland Yard is investigating whether one of those arrested is an NHS doctor.
Ronke Phillips discussed the latest developments with Nina Hossain.
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Tubes, trains, trams, buses, cable cars, river buses, taxis and going by foot - your guide to getting around during the strike.
Union officials rejected a revised offer from Underground managers during a meeting at the conciliation service ACAS this afternoon.
Train drivers were offered £200 a shift to work on the new 'Night Tube' in a bid to halt the threatened walkout.