Human rights group Liberty has launched an advertisement accusing the Government of unlawfully stirring up tension and division.
The ad-van is on the streets of London today as a response to controversial Home Office billboards advising overstaying migrants to "go home or be deported".
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Corbyn was unveiling a poster less than a mile away as Khan gave his final campaign speech to party supporters in London.
Hay fever is an allergic reaction to airbourne pollen. There are 2 million sufferers in London (that's one in 5 people).
The man suffered head injuries after falling from Westminster Bridge and landing on concrete steps.