The daughter of a man with severe depression who killed himself after having been declared fit for work says more people will die unless the Government changes the way benefits are assessed.

The Independent reported earlier this week how a coroner found that Michael O’Sullivan, 60, took his life as a direct result of being found “fit to work” by the Government’s outsourced disability assessors. The north Londoner had his disability benefits removed, despite three doctors saying he suffered from recurrent depression and his GP certifying him as unable to work.

His daughter, Anne-Marie O’Sullivan, says the way assessors ignored the expert advice of treating clinicians was behind her father’s death.

“His own GP told us he felt impotent because, despite what they said, their decision was overridden by the DWP, by the agency they employed to run these assessments, which don’t work and they have to stop,” she told ITV News. “If they continue to assess people the way they assessed Dad, we’ll continue to lose lives. Vulnerable people need support and we should be able to give them that support, we shouldn’t just let them fall by the wayside.”

Mr O’Sullivan had a long history of debilitating mental illness, including fear of being outdoors. His daughter said this meant the extra pressure of having his benefits taken away was overwhelming: “He couldn’t cope. The pressure was too much. He was a sensitive soul anyway. It was too much of a burden and he just buckled under that pressure.

“This could have been avoided ... it haunts us. Our life changed the day he left. Everything changed forever.”

Mr O’Sullivan had been on a waiting list for therapy. His daughter recalled: “Dad was under the care of his GP for many years. He also had a team of psychiatrists and psychologists and was on a waiting list to start talking therapy. He actually got to the top of the waiting list the day after his funeral and his doctors were doing everything they could to support him, but even they felt helpless, useless.”

Nearly 90 people died every month between 2011 and 2014 after they had been declared fit for work after undergoing a work capability assessment, government figures show.

Mr O’Sullivan’s suicide is believed to be the first that a coroner has explicitly blamed on the welfare reforms. Mary Hassell, the senior coroner for inner north London, wrote to the DWP about Mr O’Sullivan’s case, saying she believed there was a risk of similar deaths and demanding preventative action.

Although he died in 2013, the case has only just come to light. In a formal finding following an inquest in January last year, Ms Hassell said: “[His] anxiety and depression were long-term problems, but the intense anxiety that triggered his suicide was caused by his recent assessment by the [DWP] as being fit for work, and his view of the likely consequences of that.”

A DWP spokeswoman said: “Suicide is a tragic and complex issue and we take these matters extremely seriously.