The man behind a social media post featuring a dress that famously “broke the internet” has been sentenced to four-and-a-half years in prison for assaulting and strangling his wife.

Keir Johnston, 39, pinned his partner Grace to the ground and choked her during a row at their home on the island of Colonsay, in the Inner Hebrides, in March 2022, the High Court in Glasgow heard.

Johnston only released his wife after a witness intervened in the violent incident, the court was told on Thursday.

Johnston went on to struggle with Mrs Johnston a second time and then brandished a knife and shouted “somebody is going to die” before the witness intervened again.

The couple hit the headlines in 2015 when a picture of a dress worn by Mrs Johnston mother at their wedding ignited an online debate over its colour.

Some people said the dress was black and blue while others argued it was white and gold.

The court heard the couple had a “volatile” relationship and Johnston became enraged with his wife at their home during an argument and then tackled her to the ground and strangled her using both hands.

Johnston was said to have maintained pressure on her neck until the witness rushed at him and broke up the struggle.

Johnston uttered a threat to “finish her off”, struggled with his wife again, brandished a knife, uttered a further threat that “somebody was going to die” and then attempted to self-harm, the court heard.

Johnston pleaded guilty at the same court last month to assaulting his wife to her injury and endangering her life.

Defence lawyer Marco Guarino asked judge Lady Drummond to consider imposing a non-custodial sentence, telling the court Johnston had voluntarily sought help for his behavioural issues, was a first offender and had no other outstanding court matters.

He suggested she could sentence Johnston to carry out as much as 300 hours of community service and impose a lengthy supervision order, as well as a non-harassment order, as an alternative to custody.

Lady Drummond said she had considered Mr Guarino’s submission plus a number of background reports, including a victim impact assessment, but concluded the only “appropriate” sentence would be jail.

Speaking of Mrs Johnston’s ordeal, the judge said: “She feared for her life. The strangling lasted 20 seconds.”

Referring to the victim impact assessment, the judge said Mrs Johnston had reported feeling the incident had impacted her so severely that the memory of it would affect her “forever”.

Lady Drummond told Johnston: “She cannot understand your lack of remorse.”

She imposed a custodial sentence of 54 months, reduced from 60 months to take account of Johnston’s early guilty plea.

His sentence will be backdated to May 9 this year when he was first taken into custody.

Lady Drummond also imposed a non-harassment order banning Johnston from contacting or approaching his wife for 10 years.

Following the hearing, Police Scotland Chief Inspector Simon Shanks said: “Johnston is a violent individual who is now being held accountable for his despicable behaviour towards his victim.

“Their experience will undoubtedly have left a lasting impact however I hope that today’s outcome provides her with some degree of closure and helps them to move on with her life.

“We would encourage anyone who has, or is experiencing this type of crime, to have the confidence to come forward and make a report to Police Scotland on 101. There is no time limit on reporting and no matter when the abuse occurred you will be listened to, you will be supported and together we will bring the perpetrator to justice.”