Human rights group Black Mental Health UK and church leaders joined in welcoming the introduction of the new Corporate Manslaughter and Corporate Homicide Act, which became law on Monday.

The Act comes after 10 years of lobbying for a statutory offence of corporate manslaughter, after a number of high profile black deaths in custody as well as rail disasters, injuries and deaths on construction sites.

The law means that for the first time organisations and institutions can now be called to account when there is a death in custody. Exemptions previously removed the right of bereaved families to prosecute services when a loved one in care died due to negligence or neglect.

Manslaughter charges can now be brought against the hospital authorities. Black Mental Health hopes that the threat of prosecution will lead to the "more humane treatment" of mental health patients and a reduction in the death rate of those detained in care. Latest figures show over 300 people died while detained under the 1983 Mental Health Act in 2007 alone.

"The change in the law will put the onus on the management not to turn a blind eye to bad practice," said Mathilda MacAttram, director of Black Mental Health UK said. "We welcome this as it will make professionals who run high secure and medium secure hospitals more accountable if anything goes wrong ,so that when there is a death in custody, management know that they will be held responsible."

The death of David Bennett, an African Caribbean patient who died after being restrained by a team of five nurses, and the subsequent inquiry report threw the media spotlight on frequent human rights abuses faced by black patients in care.

Black Mental Health said the over-representation of African Caribbeans within medium and secure psychiatric settings meant that these communities were more affected by the human rights abuses highlighted in a Mental Health Act Commission report published earlier this year.

The new law will enable the courts to consider the collective actions of an organisations management and senior management teams and will no longer be reliant on having to prove one individual within an organisation guilty of gross negligience or manslaughter.

"A system where those who are culpable can no longer hide behind the institutions in order to avoid taking responsibility for the death of those charged with their care is welcomed," said Pastor Desmond Hall Chair of Christians Together in Brent.

"This hopefully will send a message to senior management who are responsible to ensure patients are kept safe and will no longer feel free to turn a blind eye to bad practice.

"We hope this changes leads to better people heading up places so that we see the death rate go down."

Rev Paul Grey, pastor of New Testament Church of God, welcomed the law but said that proper implementation would be the key to its success.

"It is good to have new safeguards that will bring organisations tasked with people's health and wellbeing into account," he said. "This legislations may well influence practice, but it is the monitoring and implementation of the Act that will make the difference in patient care.

"We will only know the true impact of this new law over time so we will have to wait to see."