Pop star Nicola Roberts has received an apology from the Crown Prosecution Service for failing to prosecute an ex-boyfriend accused of stalking her, the singer has revealed.

Carl Davies was given a lifetime restraining order in May 2017 for stalking the Girls Aloud star, and courts banned him from looking at her on social media following a conviction last year.

He was later charged with breaching the order for viewing Roberts’s Instagram, but the case was later dropped.

Roberts dated Davies for 18 months before splitting in 2008.

She told the newspaper he later bombarded her with 3,000 messages, including threats to stab and burn her.

She told the Sunday Times: “When somebody sends a message saying, ‘Those are nice pyjamas’ you think ‘is he able to see into my house?’

“You are too scared to take the dogs out for a walk because when someone plants vicious seeds you just imagine every possible outcome.

“This is a relationship which ended 10 years ago. I should be able to move on from an unhealthy relationship if I want to and that has not been able to happen for me.”

In May last year, Davies was given a 15-month prison sentence, suspended for two years, after admitting stalking the singer.

He was later charged with breaching the restraining order against her after being accused of viewing Roberts’ Instagram posts between July and August 2017.

But the CPS dropped the case because it believed there was no realistic prospect of a conviction.

A CPS statement said: “We accept our decision not to prosecute the breach of the order was incorrect.

“We have written to Ms Roberts to apologise and have taken steps to ensure lessons are learned from the case.

“We fully appreciate the impact stalking and harassment has on victims and we take prosecuting these cases extremely seriously.

“We regularly update our legal guidance to keep up with changes in technology, including social media platforms.”