A total of 91 prisoners were freed by mistake between April and October this year, according to new government figures.

The data for England and Wales was published by the government ahead of a statement in Parliament on the issue by Justice Secretary David Lammy.

The government is under pressure over accidental releases, after a number of high-profile cases in recent weeks.

The Conservatives had called for Labour ministers to reveal the latest figures, saying the public “deserve to know the truth about the scale of the security crisis in our prisons”.

The number of accidental releases has been increasing in recent years.

A total of 262 prisoners in England and Wales were freed by mistake in the 12 months to March, according to the latest annual figures, up 128% from 115 the previous year.

The latest data released by the Ministry of Justice covers a seven-month period between 1 April and 31 October.

The department said the figures cover any prisoner who is released when they should have remained in custody, where the individual or a third party did not deliberately play a role in the error.

It said the data was not directly comparable to annual figures, with the possibility of seasonal effects on releases and late recordings.

The department added that figures for recent months could change over time and in the past revisions “have tended to be upwards”.

Last week it emerged that two men had separately been released by mistake from HMP Wandsworth in the space of one week. Both men are now back in custody after police manhunts.

It came after migrant sex offender Hadush Kebatu, who arrived in the UK on a small boat, was mistakenly released from HMP Chelmsford in Essex last month.

Kebatu, who has now been deported, was living in an asylum hotel when he sexually assaulted a 14-year-old girl in Epping, triggering protests which spread across the country.