New Metropolitan Police Commissioner Sir Ian Blair wants to make London the safest city in the world.
Sir Ian headed one of the largest inquiries into police corruption
Sir Ian, 51, said an attempted terrorist attack was inevitable but believes the city's diverse communities can do much to help prevent it.
On his first day in the job he also pledged to crack down on "middle-class" drug users in London who think it is "socially acceptable" to snort cocaine.
Sir Ian joined the force in 1974 and succeeds Sir John Stevens.
Speaking to BBC News, Sir Ian said: "For the middle class drug users and all drug users that inhabit London's bars and clubs it's not the pounds that they have spent it's the misery they are causing on our estates.
"People die for cocaine and people must understand this.
"The price of cocaine is misery on the streets of London's estates and blood on the roads to Colombia and Afghanistan."
Sir Ian has pledged to do all he can to keep the city safe from terrorists, tackle anti-social behaviour, violent crime and gun culture during his tenure.
"There are people who are planning terrorist atrocities now," he said.
'Information we want'
"But these people do not carry out attacks by lightning.
"They have to plan it, they have to buy the flat, the lock-up garage, a lot of telephones at once and they have to buy strange chemicals.
"This is the information we want and this is the information we're getting."
When asked if he thought the force was institutionally racist he said: "The force has moved on massively.
"We are the biggest employer of minorities in London, we have 5,500 staff from minority groups."
Sir Ian Blair will be in charge of 2,000 community support officers
On Friday Sir John Stevens, the outgoing commissioner, said the Met needed to be tougher at rooting out corrupt officers.
In 1993 Sir Ian headed one of the largest inquiries into police corruption in London for a decade.
He told BBC News on Tuesday that there were lots of people out there that wanted to corrupt officers.
"What we have done in the last five years is ensure that both the corrupt and the corruptee both go to prison," he said.
As commissioner of the UK's largest police force, Sir Ian will be in charge of 30,000 officers and 2,000 police community officers.
He began his first day in the position at Notting Hill police station in west London, where he worked as a detective sergeant early in his career.
"We now have the resources to go further and further towards our ambition to make London the safest, major city in the world, working in the heart of the communities that make up our city," Sir Ian said.
The new commissioner said he would tackle such offences and behaviour through such measures as Safer Neighbourhoods - teams of police officers and police staff who will patrol every council ward in London.
He said he was concerned about the government's plans for 24-hour drinking and called for the drinks industry to pay their share of the extra costs of policing.
He also added his support to clarification of the rights of householders who defend themselves against intruders.
"I want it to be clear that people are not at risk of prosecution if they resist someone coming into their home," said Sir Ian.