Sadiq Khan warned Londoners on Friday that his share of council tax bills could rise by an average of almost £30 a year.
This will mean a typical household will be paying almost £425 a year to the mayor from April, in addition to about £1,500 or more to their borough council.
Mr Khan published a first draft of the Greater London Authority’s budget for 2023/24, with a “working assumption” that benchmark Band D bills will increase by £27.89 – a rise of seven per cent.
The exact rise will be published next month after the Government confirms how much support it will offer to City Hall and the 33 boroughs.
The increase includes an additional £20 for Transport for London, as revealed by the Standard earlier this week. It is likely the Met police will get about an extra £5.50, and London fire brigade about £2.30.
It means Mr Khan will oversee total annual spending of almost £20 billion, of which about £1.3billion would be funded from council tax.
In February, the mayor increased his share of council tax by 8.8 per cent, adding £31.93 to Band D bills and taking his precept to £395.59 for the current financial year.
Mr Khan said: “The last thing I want to do is raise council tax, but I want to be honest with Londoners that the Government is leaving us with no viable if we are to maintain the transport services Londoners rely on and to ensure our police officers and firefighters have the resources they need.
“I believe council tax is a regressive tax, but there are no other feasible options available to me in order to properly fund London’s vital public services.”
The mayor has become increasingly reliant on council tax to fund the TfL and the Met police, despite admitting it hits poorer people hardest.
Next year will be the second of three successive £20 annual TfL levies on council tax bills. A total of £135m of City Hall reserves are being used to limit the scale of bus cuts and to fund a scrappage scheme for the Greater London expansion of the ultra-low emission zone (Ulez).
His full budget will also set out the cost of making London “carbon neutral” by 2030. The “climate budget” will include the cost of converting all police, fire and TfL vehicles to electric, switching all heating from gas to electric or “green” energy and installing electric charging infrastructure and solar panels across GLA buildings.
But Mr Khan is said to accept that the “cost of transitioning to net zero” cannot be met by the GLA group alone and will not be at the expense of frontline services.
“The climate crisis is the biggest threat we face, and this budget will ensure London remains at the forefront of the fight,” he said.
Under current plans, the share of the council tax precept given to the Met police and fire brigade will increase by 1.99 per cent for each.
Mr Khan and Met commissioner Sir Mark Rowley believe the capital needs 1,440 more police officers than Government funding would currently allow.
