A pervert who regularly molested his sister over a decade-long period has been jailed for five years.

Alex Carr, 29, looked straight ahead of himself and did not glance towards friends in the public gallery as he was led away by cells staff this afternoon.

Sending the engineer down for half a decade, Judge Peter Crabtree said his victim had been left psychologically scarred by his abuse. He said the man had sought to persuade her to comply with his wishes, employing tactics ranging from punching her to offering to buy her gifts and agreeing to drive her to school if she missed the bus.

The judge said: “You would constantly try and collar her in your house to ask her to do it and when she got older and had a mobile phone you messaged her and texted her non-stop so she would eventually give in.”

In March, a Swindon jury found Carr guilty of two counts of sexual assault of a girl under 13 and two charges of sexual activity with a child family member aged 13 to 17. The offences were committed between 2004 and 2013.

Jurors heard the defendant had regularly sexually assaulted his sibling from the time she was around seven until she was 17. When the abuse began he was aged around 12 or 13.

She said her brother, who is five years older, had told her he began to be sexually attracted to her when they were “playing mummies and daddies” at their grandparents’ house.

Initially, she was abused in the bedroom she shared with her younger sister when the family lived elsewhere in the country.

When the family moved to Swindon from Yorkshire the abuse continued in the family home, typically in her brother’s bedroom. She described how he would “dry hump” her.

“He’d punch me. It got to the point where I was scared so I just let him. And then as I got older he’d still ask me to the point where it was constant asking, asking. I couldn’t even walk round the house without him following me round, texting and calling. I just used to give in,” she told police.

“He just used to say, ‘can we do it?’ Sometimes he’d try and tickle me. He’d get on top of me. He used to play this kissing game.”

She said her brother had promised the abuse would stop, but that he needed to perform the sex act in order to “get relief”. At one point, she was led to believe he might get cancer if she did not allow him to perform the sex act on her.

The woman claimed to have been shown an email by her brother purportedly from a professional who he had approached from support. The message suggested she needed to continue to submit herself to the sexual assaults.

Carr later bombarded her with social media messages into the early hours with pleading requests for her to come to his room. Jurors were given 81 pages of messages to read.

She eventually left home at 17, leaving behind her younger sister, father and mother – the latter suffering from a degenerative brain disease.

In a victim personal statement, read to the court on Tuesday by prosecutor Chris Smyth, the woman – now in her mid-20s – wrote: “I will never get over what my brother has done. He has left a scar both psychologically and emotionally that will never heal.”

She added: “I felt numb to what was going on because it happened so often. I felt it was normal.”

Since being found guilty at his trial, Carr had finally admitted his offending – but only to the probation officer writing a pre-sentence report.

Don Tait, mitigating, said: “Reading the pre-sentence report it is very much in the favour of this defendant that although unfortunately he committed these offences then put his sister through a trial he has come clean now and has accepted responsibility for what he did.

“He explains that he was embarrassed. He was afraid of splitting up the family.”

The barrister added: “It is clear from the evidence that this offending started when he was about 13 years of age.

“Whether or not at that age he appreciated the seriousness and the wrongness of what he was doing is a matter of conjecture.

“However, I have to concede there must have come a time if he didn’t know at the outset he later became aware what he was doing was wrong and I’d be a fool to try and suggest otherwise.”

The defendant had been diagnosed with anxiety, depression and the same degenerative brain disease that had affected his mother.

At the sentencing hearing at Swindon Crown Court on Tuesday, Carr, formerly of Greens Lane, Wroughton, was made subject to a sexual harm prevention order intended to restrict his contact with underage girls. He must remain on the sex offenders’ register for life.

The victim has waived her right to anonymity.