Police want a peaceful carnival

They were held for offences including possession of cocaine, theft and immigration offences, but have been released on bail on condition they do not go near the carnival.

Officers will use the extensive CCTV system to spot and track those breaking bail conditions over carnival weekend on 24 and 25 August.

Since the unit began work last month, it has identified those likely to cause problems at the huge event which is expected to attract over 1m people.

Up to 80 letters have been delivered across 15 boroughs to those known to police, as an extra deterrent to keep them away from carnival.

Don't be afraid about speaking out and help us to give the community of London the carnival they deserve DAC Andy Trotter More on carnival preparations

A similar operation last year resulted in 18 arrests, for offences including robbery, gun crime and burglary.

Deputy Assistant Commissioner Andy Trotter said: "It is vital that we do not allow the small minority to spoil this vibrant and unique event for many thousands of others.

"Don't be afraid about speaking out and help us to give the community of London the carnival they deserve - one of celebration not crime."

Debi Gardner, from organisers the London Notting Hill Trust Limited (LNHC) added that the safety of the public and performers was of "paramount importance".

She said: "Everyone who wants to come along to carnival and participate in the fun is welcome but troublemakers will not be tolerated."