The Metropolitan police has vowed to throw “considerable resources” at protecting this week’s expansion of the ultra-low emission zone (Ulez) amid fears the rollout will prompt a spike in vandalism and disruptive protests. The force’s declaration came as London mayor Sadiq Khan issued a fierce defence of his bitterly contested policy, saying he was acting to tackle “toxic air” and prevent the capital’s children “growing up with stunted lungs”. The Ulez will expand to cover the whole of greater London from this Tuesday. Vehicles that do not meet the emissions standards will be charged £12.50 a day, prompting claims that it will hit people already struggling with the cost of living. Advocates counter that it is needed to improve air quality and help meet targets in the UK and Europe. In many British cities, including all London boroughs, air pollution far exceeds limits recommended by the World Health Organization. Khan, who has been the subject of conspiracy theories and personal attacks over Ulez, last night conceded that the expansion was a “tough decision” but that Tuesday – when the scheme goes live – should be heralded as a “landmark day” in the move to prevent thousands of deaths from polluted air. Tensions are running high, with the Met braced for attacks on the scheme’s hundreds of fixed cameras, along with organised protests. More than 300 Ulez cameras have already been vandalised or stolen between April and mid-August and the Met yesterday admitted there had been an increase in criminality as the scheme’s expansion launch date neared. “In recent weeks, there has been an increase in criminal damage and theft to Ulez cameras and infrastructure,” said a police statement, stressing that it was treating the issue “seriously”. It also added that the force was monitoring any planned anti-Ulez protests and considering whether “bespoke policing plans” would be required. Last weekend, anti-Ulez protesters brought traffic to a standstill in Orpington, south-east London. “Some [anti-Ulez] events have seen between 200 and 300 people attending,” added the Met. Yesterday, protesters unveiled a new map showing where the hundreds of Ulez cameras are located, meaning that motorists driving within the zone might be able to calculate a journey that avoids a camera and potentially the need to pay the charge. Meanwhile, Transport for London revealed that it has spent more than £3m on an advertising campaign warning drivers of the imminent expansion of the city’s ultra-low emission zone.