Scientists capture an image of two particles interacting and sharing their physical states for an instant.
The 35-year-old woman died at the scene at a roundabout in south-west London.
A spokeswoman says the leak was "immediately contained" and there was "no risk to public health".
But leadership rival Boris Johnson says the UK will leave the EU on 31 October "come what may".
The prime minister has told the BBC that she will leave the job with a "mixture of pride and disappointment"
More than 1,000 demonstrators were arrested during April's climate change protests in London.
The PM reflects on her Brexit battles, criticism and achievements in an exclusive BBC interview.
Nyla Khan was 17 when she was forced to marry her cousin during a family holiday to Pakistan.
Ali Issa Ahmad says he was badly beaten after wearing a Qatar flag T-shirt at a match in Abu Dhabi.
The Unite union says 4,000 staff will strike over pay, but the airport says it has plans to remain open.
Darren Pencille, the man who stabbed Lee Pomeroy to death on a London-bound train, had a history of mental illness.
Ricardo Godinho, who denies murdering his wife, tells jurors he feared she would take his children.
Author Rachel Edwards said in the past people have asked her "what are you doing here?".
The judge said previous voice messages from Alex Glanfield-Collis's partner had been "chilling".
Darren Pencille stabbed Lee Pomeroy 18 times in an argument on a Guildford to London train.
Tens of thousands of spectators are expected at 18 marches marking the 1690 Battle of the Boyne.
It is understood the trial of the former first minister on charges of attempted rape and sexual assault will not begin until at least January.
Long-range thermal imaging cameras could be used by Border Force to monitor migrant boats setting sail from France.
The 33-year-old noticed a slight ache in her left breast after wearing her protective uniform.
Some Emerade pens have blocked needles so patients are advised to carry a spare one at all times.
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