London: Britain’s courts are more likely to send people from ethnic minorities to prison for certain types of crime than white people convicted of the same offences, a government-commissioned review into race and the criminal justice system has found.

Lawmaker David Lammy, who is heading the review, wrote in an open letter to Prime Minister Theresa May on Wednesday that most people from minorities who were born in Britain believed there was discrimination in the system.

“Our criminal justice system has a trust deficit,” he wrote.

May has expressed concern about the issue in the past. In her first address as prime minister, in July, she said: “If you’re black, you’re treated more harshly by the criminal justice system than if you are white.” In preliminary findings, the Lammy review reported that for every 100 white women sent to prison by Crown Courts for drug offences, 227 black women were jailed. For every 100 white men, 141 black men were imprisoned.

The exact level of disproportionality varied depending on types of offences and categories of courts, but the overall pattern was that the outcomes were worse for people from minorities.

“These emerging findings raise difficult questions about whether ethnic minority communities are getting a fair deal in our justice system,” Lammy said in a statement.

He did not give an explanation for the disproportionality, saying he would dig deeper to understand the issue and whether bias played a part. The review is due to produce a final report with recommendations next Spring.

The scope of the review has been extended by Justice Secretary Liz Truss to include the issue of lack of diversity among the ranks of the judiciary. Only 6 per cent of court judges are from ethnic minority backgrounds, compared with 13 per cent of the wider population.

Lammy is a member of the opposition Labour Party who is black and a qualified lawyer. He was widely praised for his sensitive response to the outbreak of riots in 2011 in his electoral district of Tottenham, north London, which were partly linked to distrust between black residents and the police.

His review into race and the criminal justice system was commissioned by May’s predecessor, David Cameron, in January.