Overdue police visits to sex offenders in Avon & Somerset have increased by a quarter despite government inspectors telling the force to take action to improve timings.

Chief Constable Sarah Crew says the constabulary is the "victim of its own success" in catching rapists, putting more on the register.

A report by His Majesty's Inspectorate of Constabulary and Fire & Rescue Services (HMIC) last March gave the organisation a rating of "requires improvement" on managing offenders and suspects.

It found the force had 217 overdue visits to registered sex offenders, with the longest delay being eight months.

The report said: "The constabulary should reduce the time taken to conduct visits and risk assessments on registered sex offenders."

It said that while inspectors did not find any backlog in high-risk cases, the fact the force was behind in its risk assessments meant it "may not have been aware of any developments in those low to medium-risk cases which might escalate the registered sex offender into a higher risk category".

The report added: "We found 151 overdue assessments, with the oldest again being eight months overdue.

"The constabulary must ensure that visits and risk assessments are carried out in a timely manner."

At the time, Avon & Somerset Police & Crime Commissioner (PCC) Mark Shelford, who has a legal duty to respond to the inspections, said the size of the team managing sex or violent offenders would be increased, while other offender managers would be trained to ensure there was a "greater pool or resource available to respond to this demand in a flexible way".

But the number of overdue visits has actually risen by 56 to 273, it was revealed at a meeting of the PCC performance & accountability board.

Deputy Chief Constable Jon Reilly said: "Avon & Somerset Police is in quite a unique position compared to regional forces in that we have full prisons and full 'approved premises' where people on licence are housed, and that undoubtedly has an impact on the number of sex offenders we are managing in this force area.

"In addition, both nationally and locally there is an increase in the number of registered sex offenders which increases the challenges for constabularies to meet in terms of those visits.

"In the last 11 months alone we've seen 100 additional registered sex offenders that we're managing, and that has led to some tough choices we've had to make around resourcing.

"In terms of outstanding visits, the current figure is 273, so in proportionate terms there's a slight increase in where we were when the HMIC came, out of the 1,500 offenders we manage.

"Within that number, 15 per cent are high risk, 67 per cent medium risk and 18 per cent low risk."

DCC Reilly said the visits for medium and high-risk offenders were unannounced so that officers were more likely to find evidence that required police action.

He said: "In November we undertook nearly 500 visits.

"Of those, 340 [offenders] were in, and of those we took police action in 100 cases.

"Clearly that nature means that there is always the chance someone will not be in.

"The outstanding visits now are not the outstanding visits when HMIC were here.

"This is a rolling process. Higher risk cases are very routinely scrutinised by our senior leadership team to make sure we are getting on top of those as quickly as possible.

"But nonetheless there is a gap there that we need to close quite quickly and we have taken some steps immediately."

He said this included an expansion of the offender management team and a review of how many officers should conduct a visit, in line with officer safety.

"Most importantly we have now clearly modelled our current and predicted demand over the next 12 months to ensure that we can reduce those visits to absolutely the right level they need to be," DCC Reilly said.

He said there were now 148 overdue risk assessments, so about the same as the 151 during the inspection.

DCC Reilly said some sergeants were being trained to undertake this work to reduce the delays.

He added: "So yes, there is still a backlog, we are very clear about what they are and we have a very robust plan to manage them down in the next 12 months in an appropriate way.

"I am confident we will see changes moving forward."

Conservative PCC Mr Shelford asked: "Why are the numbers of sex offenders increasing?"

Chief Constable Crew replied at the meeting on Wednesday, January 17: "We are victims of our own success. Our Operation Bluestone is charging more rapists, frankly, and we are going to see that increase."

She said the force was detecting more online child abuse, with those offenders joining the register.

Chief Constable Crew said: "This will be an area that will grow and grow for police forces and partners."