Four police officers were injured in “disorder” that broke out at an unofficial street party to celebrate Celtic winning the Scottish Premier League title.  

Police Scotland said that 19 arrests were made on Saturday as 25,000 fans thronged an area of the city centre to drink and sing. 

Officers said that they had taken “robust” action to quell any anti-social behaviour, including the setting off of pyrotechnic devices and vandalism.  

The four injured officers required medical treatment. Police have said they will work to find those responsible.  

Damage caused by the fans was branded “unacceptable” by city chiefs, after bus stops and traffic lights at Glasgow Cross were smashed by unruly fans.  

READ MORE: Police begin 'proportionate' response as thousands of Celtic fans gather

Thousands poured into Glasgow’s Merchant City yesterday after Celtic were presented with the League trophy following their 3-2 win over St Mirren.  

A Glasgow city council spokesman said as crowds dispersed in the early hours of Sunday morning, a "substantial" amount of litter, debris and broken glass was left in the area surrounding Glasgow Cross. 

An overnight clean-up operation was put in place to clear the debris, with pavements strewn with empty boxes, bottles and cans. 

Police had earlier closed off roads into the area as part of a “proportionate” response to the large gathering.  

The Herald: Thousands poured into the area Thousands poured into the area (Image: PA)

The Council spokesman said: “After an exceptional clean-up effort by our teams overnight, the area is now clear – including the course for the Cancer Research UK Race for Life, which is taking place this morning. 

“There has been damage to infrastructure such as bus stops and traffic signals, but we do not yet know the full extent of what repairs will be necessary. 

“This kind of damage, disruption and antisocial behaviour remains unacceptable. It should be possible to celebrate and show a basic level of consideration for others in the city at the same time.” 

The trophy was presented to the team at Celtic Park after the victory of St Mirren, bringing the curtain down on the football league season. A cup final with rivals Rangers is still to come.  

Last year, ten people were arrested while three were seriously assaulted at a similar gathering, with a 31-year-old man being taken to hospital in serious condition. 

READ MORE: Why Father Christmas handed Celtic the SPL Trophy

The amount of refuse left behind led to calls for the club to foot the bill, or to organise its own celebrations away from public areas. 

Superintendent John Menzies said: "I would like to thank our partner agencies and the wider public for their support. 
"Unfortunately, we experienced some disorder including the use of pyrotechnics and alcohol-related offences. We took robust action to prevent these escalating. 
"Violence and assaults on members of the public or police officers is completely unacceptable and we continue to work to identify those responsible."