The Crown Prosecution Service (CPS) has apologised to Girls Aloud singer Nicola Roberts for not prosecuting an ex-boyfriend accused of violating a restraining order for stalking her.

In May last year, Carl Davies was given a 15-month prison sentence, suspended for two years, and a lifetime restraining order after he admitted stalking the singer. He reportedly sent 3,000 messages to Roberts, including threats to stab and burn her.

He was subsequently charged with breaching the order by following Roberts on Instagram between July and August 2017, but the CPS later dropped the charges against Davies because lawyers said there was no realistic prospect of conviction.

The CPS has now issued an apology for not prosecuting the former soldier, accepting the decision was “incorrect”, and has written to Roberts to say there was, in fact, a realistic prospect of convicting Davies, according to the Sunday Times.

Roberts’ solicitor, Lisa McKinnon-Lower, of Byrne and Partners, said: “The failure in Nicola’s case was born out of a lack of understanding about how certain social media platforms work, which resulted in a decision to offer no evidence. Due to how the CPS dealt with this procedurally, no charges can now be brought.”

Roberts said she still felt scared to open her windows at night and worried about the safety of her new partner.

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

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.”