By David Mercer and Adam Arnold, news reporters
A murder investigation is under way after a shop worker was stabbed to death during a "violent robbery" at a newsagent's – one of six people to be stabbed in London in less than 12 hours.
Police were called to Marsh Food and Wine in Pinner, northwest London, at about 6am on Sunday.
The 54-year-old man was attacked as he opened up and pronounced dead about 45 minutes later. His family have been informed.
The shop's till was stolen and may have since been discarded, Scotland Yard said.
Detectives would like to speak to anyone who saw a black Vauxhall Astra driven away at speed.
"This was a violent robbery that has escalated, resulting in the murder of a man," said Detective Chief Inspector Simon Stancombe.
There have not been any arrests.
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Local business owner Peter Brook, 55, said other traders were thinking "there but for the grace of God go the rest of us".
The fatal incident came as the Metropolitan Police confirmed five other people had been stabbed – including a 13-year-old boy – in separate incidents across the capital over 12 hours.
The teenager was taken to hospital after being stabbed in Brixton, south London, shortly before midnight.
The Met Police said his injuries are not thought to be life-threatening.
A man in his 40s is in critical condition after being stabbed in Hackney, east London at about 3.15am, while two 18-year-old men suffered knife wounds in Westminster, central London, at 10.30pm on Saturday.
A 23-year-old man was also taken to hospital with non-life threatening injuries after he was stabbed in Barkingside, northeast London, shortly before 8.30pm on Saturday.