Boris Johnson is expected to dismiss several senior executives at City Hall this week but he began his time in office by announcing action on measures to curb antisocial behaviour.

Twelve key advisers, who make representations to the mayor on policy areas such as race, policing, housing and economic development, are believed to be first in the line of fire.

Mr Johnson will address staff tomorrow morning and the Tory team has not ruled out further redundancies. A key platform of Mr Johnson’s campaign was a promise to streamline the Greater London Authority. Several of the advisers had worked with Ken Livingstone for several years and were closely aligned to him. A source told The Times: “It is inevitable that Boris is going to bring in people that he knows and trusts, and who share his vision for London.”

Another layer of executives, who oversee areas such as policy and performance, are likely to remain because they are not politically appointed. There was speculation yesterday that Steve Norris, the Tory mayoral candidate defeated by Mr Livingstone in 2000 and 2004, would take on an advisory role. New advisers must be vetted by the London Assembly but the mayor can ignore its recommendations.

In his first speech as mayor on Saturday, Mr Johnson signalled that he would not tolerate unsupportive officials. “If there are any dogs in the manger, then I will have those dogs humanely euthanased,” he said.

The shake-up is likely to take place this week as Mr Johnson, who officially took office overnight, stamps his authority on City Hall. In a series of meetings with officials over the weekend, including Sir Ian Blair, the Metropolitan Police Commissioner, Mr Johnson emphasised that the delivery of his manifesto should be a priority. He is also due to meet Michael Bloomberg, the Mayor of New York.

Work has already begun on key pledges, including budgeting to provide 400 police community support officers on public transport and stripping antisocial youths of their right to free travel. Funding will come from cutting advertising budgets.

Londoners may be banned from consuming alcohol on the Tube within weeks. Staff at Transport for London have begun rewriting the rules of carriage and liaising with British Transport Police so that the measure, which Mr Johnson hopes will curb antisocial behaviour, can be implemented quickly. Mr Johnson said yesterday: “I have instructed members of my team to crack on with implementing our manifesto pledges as soon as we are physically able to do so.

“I will work night and day to deliver that change in London. A tireless approach is what Londoners demand and I will step up that challenge.”

During a visit to a cultural event in Trafalgar Square yesterday, where he was mobbed by members of the public seeking autographs and photographs, Mr Johnson said that during his meeting with Sir Ian he had demanded tough action on crime. “I made it very clear that I want to see a dramatic reduction in crime, beginning with driving out so-called minor crime, particularly in the areas for which the mayor has responsibility, and above all on public transport,” he said.

Speaking after a stabbing in which a 15-year-old boy was killed, Mr Johnson said: “I am not pretending we can transform this overnight, but it is the job of the mayor to give a lead and I won’t rest till we have started to make a difference.”

While Mr Johnson has no power over Sir Ian’s appointment he has told Tory colleagues that he will demand that Jacqui Smith, the Home Secretary, fires the commissioner if progress is not made in cutting crime.

Another priority in his first week will be an inquiry into reducing expenditure at City Hall. Mr Johnson plans big cuts, including a 20 per cent reduction in the mayor’s 70-strong media and marketing team.

LONDON MAYOR ELECTION RESULTS

Boris Johnson (C)
1st pref: 1,043,761 (42.48%)
2nd pref: 257,792 (10.49%)

Ken Livingstone (Lab)
1st pref: 893,877 (36.38%)
2nd pref: 303,198 (12.34%)

Brian Paddick (Lib Dem)
1st pref: 236,685 (9.63%)
2nd pref: 641,412 (26.11%)

Siân Berry (Green)
1st pref: 77,374 (3.15%)
2nd pref: 331,727 (13.50%)

Richard Barnbrook (BNP)
1st pref: 69,710 (2.84%)
2nd pref: 128,609 (5.23%)

Alan Craig (Christian People)
1st pref: 39,249 (1.60%)
2nd pref: 80,140 (3.26%)

Gerard Batten (UKIP)
1st pref: 22,422 (0.91%)
2nd pref: 113,651 (4.63%)

Lindsey German (Left List)
1st pref: 16,796 (0.68%)
2nd pref: 35,057 (1.43%)

Matt O'Connor (English Democrat)
1st pref: 10,695 (0.44%)
2nd pref: 73,538 (2.99%)

Winston McKenzie (Ind)
1st pref: 5,389 (0.22%)
2nd pref: 38,954 (1.59%)

The Assembly
Conservative Party: 11 seats, +2
Labour Party: 8 seats, +1
Liberal Democrats: 3 seats, -2
Green Party: 2 seats, no change
British National Party: 1 seat, +1

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