Question: On what date did the tragedy that resulted in an estimated 80 deaths, and lead to Nicholas Paget-Brown stepping down as leaderof the Kensington and Chelsea London Borough Council occur?

Context articles: Barking and Dagenham London Borough Council
Tri-borough shared services
Nicholas Paget-Brown
Kensington and Chelsea TMO
Kensington and Chelsea London Borough Council
Grenfell Tower fire
Haringey London Borough Council
Hammersmith and Fulham London Borough Council
Sutton London Borough Council
Newham London Borough Council

Barking and Dagenham London Borough Council is the local authority for the London Borough of Barking and Dagenham in Greater London, England.
 It is a London borough council, one of 32 in the United Kingdom capital of London.
 It provides a broad range of local government services including Council Tax billing, libraries, social services, processing planning applications, waste collection and disposal, and it is a local education authority.
 Barking and Dagenham is divided into 17 wards, each electing three councillors.
 At the May 2014 election, the Labour Party won all 51 seats.
 The council was created by the London Government Act 1963 as the Barking London Borough Council and replaced two local authorities: Barking Borough Council and Dagenham Borough Council.
 The council was renamed on 1 January 1980.
 The next election to the authority will be in 2018.
Tri-borough is a project between three councils in west London, England to combine service provision.
 The councils are Westminster City Council, Hammersmith and Fulham London Borough Council and the Kensington and Chelsea London Borough Council.
 It launched in June 2011 and is due to come to an end in April 2018
Nicholas Paget-Brown (born 1957) is an English Conservative politician who was leader of the Kensington and Chelsea London Borough Council.
 He was first elected as a councillor for Hans Town on 8 May 1986.
 He became leader of the council on 23 May 2013.
 On 30 June 2017, he announced that he would step down as leader due to the council's response to the Grenfell Tower fire, and was replaced as leader by Conservative Elizabeth Campbell on 19 July 2017.
Kensington and Chelsea TMO (KCTMO) is the largest tenant management organisation (TMO) in England, running nearly 10,000 properties on behalf of Kensington and Chelsea London Borough Council – the entire council housing stock in the Royal Borough of Kensington and Chelsea.
Kensington and Chelsea London Borough Council is the local authority for the Royal Borough of Kensington and Chelsea in Greater London, England.
 It is a London borough council, one of 32 in the United Kingdom capital of London.
 Kensington and Chelsea is divided into 18 wards, each electing three councillors.
 The council was created by the London Government Act 1963 and replaced two local authorities: Kensington Metropolitan Borough Council and Chelsea Metropolitan Borough Council.
 The borough council provides some shared services with Hammersmith and Fulham, and Westminster.
The Grenfell Tower fire occurred on 14 June 2017 at the 24-storey Grenfell Tower block of public housing flats in North Kensington, Royal Borough of Kensington and Chelsea, West London.
 It caused an estimated 80 deaths and over 70 injuries.
 A definitive death toll is not expected before 2018.
 As of 27 September 2017, 68 victims had been identified by the Metropolitan Police and Coroner.
 Occupants for 23 of 129 flats died.
 Around 255 people survived.
 Inquests for 60 known victims were opened and adjourned at Westminster Coroner's Court.
Haringey London Borough Council is the local authority for the London Borough of Haringey in Greater London, England.
 It is a London borough council, one of 32 in the United Kingdom capital of London.
 Haringey is divided into 19 wards, each electing three councillors.
 Haringey London Borough Council comprises 48 Labour Party councillors, and 9 Liberal Democrats.
 The council was created by the London Government Act 1963 and replaced three local authorities: Hornsey Borough Council, Tottenham Borough Council and Wood Green Borough Council.
 The next election to the authority will be in 2018.
Hammersmith and Fulham London Borough Council is the local authority for the London Borough of Hammersmith and Fulham in Greater London, England.
 It is a London borough council, one of 32 in the United Kingdom capital of London.
 Hammersmith and Fulham is divided into 16 wards, electing a total of 46 councillors.
 The borough council provides some shared services with Kensington and Chelsea, and Westminster.
 The council was created by the London Government Act 1963 as the Hammersmith London Borough Council and replaced two local authorities: Hammersmith Metropolitan Borough Council and Fulham Metropolitan Borough Council.
 The council was renamed on 1 January 1980.
Sutton London Borough Council is the local authority for the London Borough of Sutton in Greater London, England.
 It is a London borough council, one of 32 in the United Kingdom capital of London.
 Sutton is divided into 18 wards, each electing three councillors.
 Following the May 2014 council election, Sutton London Borough Council comprises 45 Liberal Democrat councillors and 9 Conservative Party councillors, an increase of the Liberal Democrat majority.
 The council was created by the London Government Act 1963 and replaced three local authorities: Beddington and Wallington Borough Council, Sutton and Cheam Borough Council and Carshalton Urban District Council.
Newham London Borough Council is the local authority for the London Borough of Newham.
 It is a London borough council, one of 32 in the United Kingdom capital of London.
 The council is unusual in that its executive function is controlled by a directly elected mayor of Newham, currently Robin Wales.
 Newham is divided into 20 wards, each electing three councillors.
 Newham London Borough Council comprises 59 Labour Party councillors and a solitary councillor expelled, with immediate effect from the Labour Party in 2017.
 The council was created by the London Government Act 1963 and replaced three local authorities: East Ham Borough Council, West Ham Borough Council and Woolwich Metropolitan Borough Council.