"Thugs ambushed a Met vehicle patrolling streets in an area of north London close to where violence sparked four days of disorder across Britain. Scotland Yard is deploying more than 10,000 police officers on the streets amid fears of further outbreaks.

The move comes as London is put on alert for the Notting Hill Carnival this weekend. Extra officers were sent to the scene in Fore Street, Enfield, after the petrol bombs were thrown at 11.30pm last night. Scorch marks and evidence of accelerant were found at the scene.

Senior officers fear the annual bank holiday carnival may be used as an excuse by yobs to go on the rampage. Event organisers say they have beefed up security and drawn up contingency plans in case trouble breaks out.

There have been heightened concerns about the carnival in the wake of the widespread rioting that rocked London a fortnight ago. The Met has arrested nearly 2,000 people after violence broke out in 22 London boroughs before spreading across England.

Police expect this year's carnival to be down on numbers, despite Boris Johnson's pledge that it will be "robustly policed".

Police have arrested 40 suspected gangsters plotting to cause trouble at the event. They have picked up "chatter" on social network sites about plots to disrupt it but say there is no evidence that people are plotting widespread looting.

All leave has been cancelled as the Met deploys the largest ever number of officers at the event.
Four thousand are being drafted in from outside forces to police the rest of London.

The riots were set off by a march to Tottenham police station by friends of suspected criminal Mark Duggan, who was shot by armed officers as he was being arrested. He was in possession of a handgun.

Tottenham borough commander Sandra Looby today defended police handling of the riots. She said: "At no point did we receive information this was going to turn into the spontaneous criminality that subsequently happened."

Taken from London evening standard  http://www.thisislondon.co.uk/standard/article-23981229-petrol-bomb-thugs-attack-police-london-on-alert-for-carnival-weekend.do