Scotland Yard has been accused of “blatant discrimination” after an officer warned local businesses of the risk of hosting mourners from the Traveller community attending a funeral.

The warning to the businesses in the London borough of Barking and Dagenham prompted representatives of the Traveller community to send a complaint to the policing watchdog and to the Met commissioner, Cressida Dick.

Community leaders said the incident further soured the already strained relationship between the police and the Traveller community.

Last month a local police officer warned licence holders in Barking and Dagenham that “intelligence has been received that there is a very large-scale Travelling community funeral wake today in the borough of Barking and Dagenham”.

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The officer wanted licence holders to be aware of the “very high risk of incidents” if their premise was the intended destination. He called on businesses to inform the police if they did get a visit so that resources were available “in the event of any incidents”.

The email has been described as another glaring example of racial profiling and systematic discrimination from the police.

Last year there was widespread anger and frustration after many pubs and shops closed across Hertfordshire and Essex on the day of the funeral of a girl who died after being hit by a train. A local JD Wetherspoons defended the decision to close the pub, claiming the move was endorsed by the police.

Yvonne MacNamara, the chief executive of the Traveller Movement, said the charity was “deeply concerned that yet again we see this blatant discrimination from the police. We have previously raised concerns with the Metropolitan police and referred these complaints to the Independent Police Complaint Commission which were upheld.”

MacNamara said racial profiling was “without question an issue” in the force. “Unfortunately we are not seeing the redress or systematic policy changes that are urgently needed to prevent this dangerous broad-brush policing approach towards these communities.”

The Gypsy, Roma and Traveller Police Association (GRTPA) said the email demonstrated how the ethnicity of Travellers was “widely used as a risk factor within the Metropolitan Police Service and across the country.”

The association said such incidents did little to improve the recruitment and retention of Gypsies, Roma and Travellers to the force. It criticised “an environment where it’s OK and indeed indirectly encouraged to say ‘Traveller incident’, ‘Travellers causing issues’ and ‘Traveller children causing ASB’. If you replace Traveller with any other ethnicity this would just be unacceptable, it would be terminal for your career and rightly so.”

Last year the home secretary, Priti Patel, proposed a new law criminalising unauthorised Gypsy and Traveller encampments. Police responses to a consultation launched last year about dealing with such encampments show forces are opposed to such a move.

Daniel Cooper, of Imran Khan & Partners Solicitors, who is representing the Traveller Movement, said: “The police have repeatedly said that there is no room in their ranks for discrimination. This incident shows that this does not appear to be the case. Urgent action is required at the highest levels to address what has happened and a failure to do so will leave our client with no choice but to seek legal action against the police.”

A spokesperson for the Met said: “A complaint was received on Friday 7 February. The content of the complaint will be assessed.”