Every area saw a significant increase in coronavirus cases, with 20 boroughs having their rates more than double - and eight having the rates triple.
The shocking statistics show London has become the Covid-19 epicentre of the UK, mainly due to the ultra-transmissible variant Omicron.
The only two local authorities outside London in the UK’s top 20 Covid hotspots were Brentwood and Elmbridge, which border the capital to the east and south-west.
The government figures show that in the week to December 16, a whopping 131,061 tested positive for Covid-19 in London.
The highest rate was in Lambeth, which also had the highest rate across the UK.
Around one in 40 people caught Covid-19 in the south London borough, a rate of 2,477 per 100,000 people.
That was a massive increase of 263%, on the previous week - with 7,972 new cases.
Neighbouring Wandsworth had the second highest Covid-19 rate in both London and the UK, with a rate of 2,383 per 100,00.
This meant about one in every 42 people tested positive in the week to December 16.
That was a 242% rise on the previous week.
While Hackney and the City of London, which are grouped together, were ranked third in London and the UK.
They had a Covid-19 rate of 2,112 per 100,000, with a increase in cases of 250%.
Southwark, Hammersmith and Fulham, Islington, Lewisham, Tower Hamlets, Merton and Haringey rounded out the UK top 10.
See how your borough fares in our table and interactive map.
As the map shows, the high Covid-19 rates are centred around the inner London boroughs, and particularly in south London.
He revealed that last week, the number of Covid-19 patients in London hospitals had gone up 29% - the largest rise in England.
Mr Khan said: “The surge in cases of the Omicron variant across our capital is hugely concerning, so we are once again declaring a major incident because of the threat of Covid-19 to our city.
“The Omicron variant has quickly become dominant with cases increasing rapidly and the number of patients in our hospitals with Covid-19 on the rise again.
“We are already feeling the impact across the capital and while we are still learning about this variant, it’s right that London’s key agencies work closely together to minimise the impact on our city, including helping to protect the vital vaccination programme.”
Major incidents were previously called for Grenfell Tower and terror attacks, and means a strategic coordinating group will be established with a government representative on board.