He intends to pay for the extra resources required to combat the Met's problems by cutting staff in its press office from 73 to 50 and halving its £3.1 million publicity budget.

During his election campaign, Johnson made the fight against street crime among London's youths the priority for his mayoralty.

In the past, the Conservative Party has criticised the “excessive use of public spending” on such campaigns.

However, the move to curb ad spend will also lead to less publicity for schemes such as the congestion charge, recycling and anti-drugs drives.

The cuts are not expected to spark an agency review. The roster agencies for GLA include Farm Communications, Spirit Advertising and WCRS. MCBD handles the advertising for the Met Police.

Last month, local councils were attacked for spending too much on marketing, middle management and pension schemes by the Taxpayers’ Alliance, which said cutting budgets by 10 per cent could lower the average council tax bill by £40.

The campaign group said in 2006/07 England and Scotland spent a total of £6.6 billion on these three “non-priority” areas.

Johnson is also planning to enforce his election promise of banning the consumption of alcohol on London's transport system as part of a wider strategy to tackle anti-social behaviour.

The mayor plans to get the message across with new posters to be unveiled advising passengers of the no-alcohol policy across the transport network including the underground and at bus stops.