Jack Dorsey, Twitter chief executive, said the company's efforts had led to "diluted" solutionsAMAL KS/HINDUSTAN TIMES/REX/SHUTTERSTOCK

Twitter leaves some of its users at risk of physical harm and puts too great a burden on victims of abuse, its co-founder and chief executive has admitted.

Jack Dorsey said that the app's "vibe" depressed him and he described efforts by the platform to put its house in order as a "huge fail".

Twitter has been heavily criticised over its failure to tackle abuse, hate speech and bullying. Amnesty International reported in December that more than 7 per cent of 1.1 million tweets mentioning 778 female journalists and politicians from Britain and the US were "abusive" or "problematic".

Public figures who have been targeted with vile abuse include the Labour MPs Diane Abbott, Luciana Berger and Yvette Cooper. This month a man was arrested…