Emergency services are warning those attending the Notting Hill Carnival to avoid legal highs.

The London Ambulance Service (LAS) said legal highs, such as nitrous oxide, known as laughing gas, were a big problem at the carnival last year.

LAS tactical commander for the carnival, Paul Gibson said: “Legal highs can be extremely dangerous. We urge people to think twice before taking them and be aware of the potentially harmful side effects.”

Police said it would have 6,000 officers on duty on Sunday (August 30), and 7,000 on Bank Holiday Monday, and that it would be on the look-out for trouble-makers.

Met Police superintendent Robyn Williams, spokesperson for this year’s event, said: “We want visitors to enjoy themselves safely. Unfortunately given the large number of people the event attracts, there will always be some who see it as an opportunity to commit crime.

“I say to those who plan to cause trouble, do not come. We will do everything in our power to make things difficult for you.”

This week the Met made 143 arrests as part of a London-wide operation targeting gang crime, drugs supply and other offences that could impact on the Carnival.

An anti-social behaviour dispersal zone will also be in place from 7am today (Sunday, August 30), until 6.59am on Tuesday, September 1.

During this period, a police officer can ask a person to leave the area if they are contributing or are likely to contribute to anti-social behaviour. If the person refuses to leave, or returns within 48 hours, they commit an offence and are liable to be arrested.

Superintendent Williams added: “Creating a safe environment for Europe’s biggest street party is a priority.”

Speaking about the problems caused by legal highs last year, Mr Gibson said: “We treated many people who presented symptoms having taken legal highs. These included seizures, falls and people suffering injuries as a result of assaults.

“Legal highs can be extremely dangerous. We urge people to think twice before taking them and be aware of the potentially harmful side effects.

“As ever we want revellers to stay safe and healthy whilst having fun at the carnival.”

Notting Hill Carnival coverage