The police unit dedicated to investigating violent crime in London's black communities is at risk of being disbanded because of government cuts, the Guardian has learned.

Operation Trident, set up 12 years ago to tackle a rise in gun attacks among London's African-Caribbean community, may be merged with other Metropolitan police crime squads following the comprehensive spending review.

A high-ranking officer raised that possibility at a meeting of Trident's independent advisory group earlier this month, a senior police source said.

The disclosure prompted anger from leading black figures who believe that Trident, backed by high-profile campaigns and a dedicated intelligence unit, has improved the often distrustful relationship between police and black people in London.

Diane Abbott, Labour MP for Hackney North and Stoke Newington, said any plans to scrap Operation Trident would be "ludicrous and dangerous".

She said: "I have great respect for the work that Trident does. Rather than scrapping Operation Trident, the Met should be extending its methods to other communities with similar issues. Gun crime is on the increase in London, and in my constituency of Hackney, Operation Trident plays a huge part in solving crimes on a day-to-day basis. Cutting backs its efforts would be a huge loss and will put Londoners at greater risk of further highly dangerous crimes," she said.

Claudia Webbe, head of the Trident independent advisory group, declined to comment on the meeting held two weeks ago, but said she and other advisory group members were "clearly worried" by what could happen to Trident following government cuts. "Trident has successfully demonstrated that it is a powerful partnership between the police and the community in tackling the disproportionate effects of gun crime on black communities ... despite previous policing failures and charges of 'institutional racism'.

"We argued that building trust and confidence and encouraging witnesses and members of the community to come forward and work in partnership with the police was critical to solving gun and violent crime. This approach requires sensitivity, dedicated police time and specialist resources," she said.

Operation Trident was set up in 1998 in response to the murders of Avril Johnson, a DJ from south London, and Michelle Carby, from east London, who were gunned down in their homes.

The killings came amid fears of a wave of gang-related violence linked to crack cocaine trafficking and a more aggressive gun culture. Officers were finding the cases difficult to investigate as fear of reprisals meant witnesses were afraid to come forward, and there was a general distrust of the police.

The unit, the first of its kind in Britain, was established to help officers in local police stations investigate shootings and collate intelligence from across the capital on suspected gunmen, firearms suppliers and gun converters. It now has 350 investigative officers and 98 support staff. Since April this year, it has investigated 224 shootings, including 12 murders.

Over the past 12 years, the unit has conducted more than 300 successful investigations, including the conviction in 2004 of Owen Clark, aka Father Fowl – a drug kingpin whose operation, involving crack cocaine and gun crime, stretched from north-west London to the Caribbean.

Tactics used by the unit have been reportedly transferred to other cities including Birmingham, Manchester, Bristol and Liverpool.

All police forces are facing a 20% cut in funding following the spending review. The accountancy firm KPMG has estimated that 18,000 officer and civilian posts nationwide could be at risk, but frontline cuts could be avoided if radical workforce reforms go ahead.

But the home secretary, Theresa May, argues that the actual cut in police budgets is unlikely to be more than 14% over four years.

Sir Paul Stephenson, the Met's commissioner, is believed to have been told the level of the Whitehall police grant in recent days and is finalising detailed estimates of job losses. A spokeswoman for Scotland Yard confirmed that changes to Trident were a possibility, but nothing had been finalised. "[Trident Operational Command Unit] remains committed to working with London communities to prevent and investigate shootings and is reviewing all options on how it can deliver a better service to Londoners at a time of reducing budgets. However, at this stage, no decisions have been made.

"The Trident independent advisory group offers strategic and tactical advice to the Metropolitan police. They have been, and will continue to be, consulted on how Trident can prevent shootings and bring those responsible to justice. We remain committed to continuing to deliver a better policing service for less by streamlining our business support and making best use of our operational assets," she said.

In numbers: Incidents during Operation Trident

2010/11 to date: 224 shooting incidents and 12 murders

09/10: 342 shooting incidents and 7 murders

08/09: 223 shooting incidents and 14 murders

07/08: 275 shooting incidents and 18 murders

Murders only

2005/06: 15

2004/05: 18

2003/04: 12

2002/03: 24

2001/01: 22

Source: Met and BBC