The TUC are calling for the government to increase the minimum wage and do more to encourage businesses to pay their staff the living wage.
Geoff Tily, Senior Economist at the TUC said it was time for the government to take decisive action to help working families living in poverty due to low pay.
Half of workers in Harrow West are currently being paid less than the minimum wage, according to new figures released by the TUC.
The research, based on ONS figures, show a number of pay 'black spots' across the capital.
The London living wage is currently set at £9.15 per hour.
Almost half of Londoners living in some boroughs earn less than the living wage, according to new figures released by the TUC.
The London living wage is currently set at £9.15 per hour, compared with £7.85 across the rest of the country.
Nationally, more than five million people earn less than the living wage.
The rate is set by the Living Wage foundation and calculated by the Greater London Authority to cover all boroughs in Greater London.
The Mayor of London will be stepping behind the coffee counter today as part of his launch of a new rate for the London Living Wage.
Boris Johnson will be marking the beginning of Living Wage week at the first coffee shop in the city to commit to paying the increased wage.
The London Living Wage is calculated on an hourly rate based on the combination of the cost of living in the city and 60 percent of the median wage.
New research by the London Assembly shows that two thirds of London boroughs have not been accredited as London living wage employers.
The Assembly's Economic Committee found that those who have been accredited are failing to persuade private social care providers to pay their staff a living wage.
Progress has been particularly slow in the hospitality, cleaning and social care sectors.
The London living wage is £8.80 per hour compared to a minimum wage of £6.31 per hour.