The move comes after the four-week delay to the end of Covid restrictions was announced on Monday.
The Notting Hill Carnival has been cancelled for a second year in a row because of the ongoing coronavirus pandemic.
The organisers of the festival, which is the biggest street party in Europe, said it had decided that this year's event in London "will not be on the streets due to the ongoing uncertainty and risk COVID-19 poses".
The event will once again be online, as it was in 2020.
In a statement, the board of Notting Hill Carnival Ltd said: "This has been an incredibly difficult decision to make.
"Everyone involved in the event desperately wants a return to the road where carnival belongs but safety has to come first and with the latest cautious announcement on the government's roadmap, this is the only way to ensure that.
"In making this decision, we have considered our responsibilities to deliver a safe, spectacular, successful and sustainable carnival.
"The conclusion is that with so much uncertainty, with time short for carnivalists to prepare and the risk of eventual cancellation a real possibility, we must refocus our efforts for 2021."
https://twitter.com/NHCarnivalLDN/status/1405812623661273090
Earlier this year, the chief executive of Notting Hill Carnival Ltd, Matthew Phillip, had told MPs that it would be "very difficult" to hold the Caribbean carnival if social distancing was in place.
He said: "It would be very difficult to hold carnival in its traditional format on the streets with social distancing in place. It would be devastating for a second year in a row."
The carnival is the biggest in Europe, and globally is second only to Brazil's famous Rio carnival in terms of size.
The festival is rooted in Caribbean culture and usually last three days, featuring music, dancing, food and drink. It has been heavily influenced by the Windrush generation throughout its history.
