She added: ‘I thank the police who have tonight shown great bravery and calm in the face of disgraceful violence directed at them.’
It comes as Hampshire Police yesterday confirmed that one of the officers involved in Mr Nowak’s arrest had resigned.
Three of the officers involved are still serving, the force added, while all four are being treated as witnesses in an investigation by the police watchdog.
Earlier, a different officer received death threats and was ‘forced to relocate’ after being wrongly identified online as being involved in the case, Ms Mahmood said.
The officer had to relocate for the safety and security of his family, the Home Secretary told the House of Commons.
Digwa was jailed for life with a minimum term of 21 years on Monday for stabbing Mr Nowak six times with a religious blade he was carrying.
A day later, demonstrators arrived in Southampton holding pictures and banners, with clips shared online showing crowds carrying Union flags descending upon the police station.
A large police presence was put in place outside the station, with officers forming a blockade.
In a video posted on social media, far-Right activist Tommy Robinson described the footage of Mr Nowak’s arrest as ‘horrific’ while calling on supporters to attend the protest.
Robinson, Right-wing commentator Laurence Fox and UKIP leader Nick Tenconi were among those who stood at the steps of the police station as speeches were delivered to the crowd.
The Lord’s prayer was said twice, while Robinson argued that ‘white people are treated like second-rate citizens’ in his speech.
In one chant, hundreds of people shouted ‘I can’t breathe, I can’t breathe’ in reference to what Mr Nowak told police as he lay dying on the ground.
Tenconi told the crowd: ‘Hampshire police must sack and arrest the arresting officers.
‘They must publicly take the knee for Henry Nowak.’
A fire rages behind a line of riot police as officers clashed with protesters in Southampton
More than 1,000 demonstrators attended last night’s protest, many of whom carried Union flags
A police helicopter hovered overhead as officers were pelted with stones
A protester who covered his face throws a bin at police during violent clashes
Police dog handlers stand behind the line of officers near Portswood Police Station in Southampton
Protesters in Southampton before the gathering turned violent
An image issued by the Crown Prosecution Service shows the eight-inch ceremonial dagger used by Digwa
Digwa’s father Moga Singh, left attempted to hide his face as he appeared at Southampton Magistrates’ Court yesterday alongside his son Gurpreet Digwa