The Government could trigger an emergency plan to avoid prison overcrowding “at some point next week” as rioters are sentenced, according to the Prison Officers’ Association.

It followed reports in The Observer that the Government could be about to trigger Operation Early Dawn.

The long-standing contingency measure allows defendants to be held in police cells until prison beds become available, but could mean their court dates are delayed or adjourned at short notice.

Mark Fairhurst, the national chairman of the Prison Officers’ Association (POA), said the measure risks “clogging up police cells”.

He told BBC Radio 4’s Broadcasting House on Sunday that an announcement could come as early as Monday morning.

Mr Fairhurst said: “This is all a result of the rioters. Last week, we had the biggest influx of new receptions I’ve seen for quite some time.

“We had 397 new receptions. As of Friday we only had 340 spaces left in the adult closed male estate which is feeling the most pressure.

“I wouldn’t be surprised if at some point tomorrow morning the Ministry of Justice would announce that Operation Early Dawn kicks in to play at some point next week, probably Tuesday onwards.”

Mr Fairhurst said the move would put pressure on police forces.

He added: “You’re now clogging up police cells, so they haven’t got the power to arrest people and put them away in a police cell.

“It has a massive knock-on effect on the entire criminal justice system.”

After the riots that broke out across England following the stabbing of three girls in Southport, a total of 460 people had appeared in magistrates’ courts relating to the disorder by the end of Thursday.

Mr Fairhurst warned pressure on the prison system is “really, really tight”, and offenders in the most pressured regions faced sentences far from home.

He said: “The pinch points at the moment are the North East and the North West, so it’s likely that if you commit an offence in those areas you will be carted 100, 200 miles away from home to serve your sentence because there’s simply very few spaces.”

Line of police officers in protective gear
Recent unrest has led to hundreds of people appearing in court (PA)

A Ministry of Justice spokesperson said: “This Government will always make sure we have the prison places we need, and we have taken decisive action to see criminals who break the law swiftly brought to justice.

“We will update on operational decisions in the normal way.”

Last month, the Ministry of Justice said violence and self-harm in prison had risen to “unacceptable” levels as overcrowding pushed jails to the “point of collapse”.

Justice Secretary Shabana Mahmood announced plans to cut the proportion of the sentence inmates must serve behind bars from 50% to 40%.

The temporary move – which does not apply to those convicted of sex offences, terrorism, domestic abuse or some violent offences – is expected to result in 5,500 offenders being released in September and October.

Last Monday, the Government confirmed those involved in recent unrest will not be excluded from its plans to release some inmates from jail early.

MPs have already approved the laws allowing the plan to be put into action and any changes could require updating the legislation in a short space of time if additional exemptions were to be included.

Operation Early Dawn was previously triggered by the Conservative government in May in a bid to tackle overcrowding in jails.