Boris Johnson pledges to slash council tax every year

Mr Johnson plans to reduce his share of the tax, which funds Transport for London, the fire authority, the Met Police and the Olympics, if he wins the battle for City Hall on May 3.

Sir Edward Lister, Mr Johnson's chief of staff and deputy mayor for planning, said further reductions will be made by making around £150 million of savings during a second term in office.

He also attacked Ken Livingstone, saying that he had turned City Hall into a "financial basket case".

Earlier this month the Mayor announced that he will cut his share of the council tax for the first time in a move that he claimed was a break from the "contempt for London taxpayers" shown by his Labour rival. He reduced the precept by one per cent.

But the Mayor was attacked by critics who pointed out that the precept will fall from £309.82 to £306.72 - a saving of just £3.10 a year. Mr Johnson will now look to cut council tax significantly every year if he wins the election, Sir Edward said. Savings of £150 million could potentially translate into a cut of around 10 per cent over four years, though City Hall sources said some of that money could be spent elsewhere.

Sir Edward, who gained a reputation as a fearsome cost-cutter during 19 years at Wandsworth council, told the Standard that more than 500 posts have been cut within the Greater London Authority family since 2008, saving around £30 million a year on staff costs. When the London Development Agency, the Mayor's economic regeneration body, is moved in-house to City Hall 400 jobs will go.

The Homes and Communities Agency London, which is also coming under City Hall's control, will have its numbers cut from 80 posts in 2008 to 45.

"There were nearly 1,400 people working in the GLA and its various bodies in 2008," Sir Edward said. "In these last four years 530 people have gone but we've absorbed bodies such as the LDA into City Hall.

"This place was a basket case when Boris took over. City Hall was a very bloated bureaucracy. The reduction in staffing levels we have made so far is roughly £30 million worth."

Sir Edward added: "We're looking at staffing levels as well as efficiency savings of around £150 million over the next four years. That would translate to further savings in council tax. The one per cent cut this year was a down payment - nothing more."

Labour Mayoral candidate Mr Livingstone has pledged to cut transport fares by seven per cent if elected to wipe out a series of inflation-busting fare rises.

His spokesman said: "While Ken has concrete pledges which would save Londoners on average £1,000 over four years, Boris Johnson offers little more than spin and fare hikes which are hitting us all in the pocket."