Previously confidential files reveal concerns over Margaret Thatcher's commitment to the Anglo Irish Agreement, two weeks before it was signed.

The Islamic State group releases a video appearing to show militants killing a Kurdish man as a warning to forces fighting it in northern Iraq.

US President Barack Obama accuses Russia of being responsible for the violence in eastern Ukraine, as Nato prepares to hold an emergency meeting.

Andy Murray makes short work of German qualifier Matthias Bachinger as the Briton advances to the US Open third round.

A study of genetic sequences sheds light on the settling of the North American Arctic, from ancient "Paleo-Eskimos" to the modern-day Inuit.

Nigel Farage says more disaffected MPs could join UKIP if it is successful in the by-election caused by the defection of Tory Douglas Carswell.

A study of smokers in Australia suggests there is "no evidence" that the introduction of standardised cigarette packaging has changed the way people buy cigarettes.

The Icelandic Met Office raises its aviation warning level near the Bardarbunga volcano to red after an eruption began overnight.