Coronavirus infection rates appear to have dropped across London, with all but five boroughs reporting a decrease on last week’s figures.

The figures – covering the seven days to September 17 – are based on tests carried out in Government laboratories and in the wider community.

The sharp drop in confirmed positive cases comes amid concerns over the national testing system as it is widely believed the epidemic is spreading.

With medical and scientific chiefs warning that the virus is spreading fast, the number of positive cases would be expected to rise.

So the figures suggest hundreds of cases in the capital may be going untraced, which risks fuelling the spread of the disease if these individuals are continuing to go to work, to socialise, to visit the pub and see friends, rather than self-isolating.

Or, which would be good news, the fall in cases could actually reflect the true picture in the capital of a disease in retreat after the “Rule of Six” was introduced.

Wandsworth has seen its number of weekly confirmed cases more than half in the past week, from 105 reported on September 10 to 51 on September 17.

Lambeth also reported significant reduction – from 97 new weekly Covid-19 cases down to 50.

Only Waltham Forest reported a significant rise in infections, with 73 new cases compared to 53 last week – marking a 38 per cent increase.

Redbridge remains the worst-hit local authority – recording 130 new cases at a rate of 42.6 per 100,000.

Infection rates in 14 boroughs are now above the Government's threshold for imposing quarantine restrictions on holidaymakers returning to the UK from abroad – with 20 per 100,000 considered high risk.

Redbridge, Barking and Dagenham, and Havering have all reported infection rates of more than 30 per 100,000.

Boris Johnson will chair a Cobra meeting tomorrow morning to discuss the next steps in the UK's coronavirus response.

Ahead of the meeting, the Prime Minister will phone the first ministers of Scotland, Wales and Northern Ireland, while the Cabinet received a detailed briefing from the Government’s chief medical, scientific and economic advisers over the weekend, Mr Johnson’s official spokesman said.

In a briefing to the nation on Monday, chief medical officer Chris Whitty hinted at new social curbs to prevent an "exponential" rise in deaths as he called for Brits to "break unnecessary links between households", warning that the "vast majority" were still "susceptible" to Covid-19.

Meanwhile, Health Secretary Matt Hancock told the Commons people on low-incomes who need to self-isolate with Covid-19 will be eligible for a £500 payment from next Monday.