The Union flag is flown at half mast in Downing StreetCredit:PA The UK will observe a minute’s silence on Tuesday, June 6, and flags will remain at half-mast on Whitehall government buildings, Downing Street has announced.The silence will be held at 11am in remembrance of those killed and hurt by the attacks in London on Saturday evening.Londoners can also attend a vigil in Potters Fields Park beside City Hall tomorrow evening from 6pm. Flags across the country have already been flying at half mast after seven people were killed in a van and knife rampage by three terrorists on London Bridge and nearby Borough Market in Southwark. The event was announced on the Mayor of London’s website with the message: “The Mayor invites all Londoners – and everyone visiting our city – to come together in solidarity to remember those who have lost their lives in Saturday’s attack, to express sympathy with their families and loved ones and to show the world that we stand united in the face of those who seek to harm us and our way of life.”We will never let these cowards win and we will never be cowed by terrorism.”Members of the public will be able to lay floral tributes at the flagpoles at City Hall.” The attack comes only two months after Khalid Masood mowed down crowds on Westminster Bridge, killing five people and less than two weeks after Salman Abedi killed 22 when he blew himself up at an Ariana Grande pop concert in Manchester. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.