New Year, but the same old shocking scenes: Mayhem in streets across Britain as drunken revellers lose their senses (and in some cases their trousers) Read more: http://www.dailymail.co.uk/news/article-3380899/Where-streets-no-shame-New-Year-revellers-spill-pubs-clubs-night-drunken-excess-Britain.

It has been a night of wild celebrations and drunken mayhem across Britain as New Year revellers welcomed 2016 by hugging police cars, rolling around in the street and, in some cases, losing their trousers.

Millions of party-goers packed out pubs and clubs, with some braving freezing temperatures, while in the Welsh town of Aberystwyth one woman was seen lying in the road as she and a friend waved goodbye to 2015.

Another was pictured wrapping her arms and legs around a police car.

Revellers were also seen looking a little worse for wear in Swansea, vomiting outside takeaways, being helped off the pavement and having to be carried away as their trousers fell down.

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One man was also seen with his jeans part way down as he was detained by police.

In London, a reveller was taken away on a stretcher while dozens more were tended to by the emergency services and temporary treatment centres. Some were handed blankets after braving temperatures below 0C in parts of the country.

There were a total of 48 arrests in the capital overnight, including four for drug possession, three for carrying offensive or bladed weapons and five for assaults on police officers.

Six people were also detained for public order offences, 11 for assault and one for sexual assault, the Met said. 

West Midlands Ambulance Service, which put a record number of crews on duty, dealt with 1,629 emergency call-outs between 8pm on New Year's Eve and 4am on New Year's Day.

A spokesman said a man aged in his late teens was successfully resuscitated using a defibrillator after suffering a cardiac arrest outside a nightclub in Broad Street, Birmingham, shortly after 1am. 

Thousands of people had gathered on the banks of the River Thames for a stunning midnight display featuring around 12,000 fireworks.

But it was what they left behind that was just as eye-opening, as the clean-up operation began in earnest to rid the streets of rubbish. 

As revellers made their way home, one woman was seen carrying an inflatable Zimmer frame, while others had to help up friends who had fallen down.

The scenes were similar to that witnessed on 'Black Eye Friday', known as Britain's booziest night of the year. The final Friday before Christmas, it saw Britain's towns and cities descend into chaos as binge-drinkers hit the streets in their droves.

Police cells in Plymouth were full by midnight as officers dealt with incidents of violence, drunkenness and disorder on their busiest night of the year. And medics in Wales were forced to open a makeshift Accident and Emergency ward in the streets of Cardiff to deal with the fall out. 

On New Year's Eve, those in the capital were watched over by every available officer at the Metropolitan Police's disposal, including hundreds of firearms personnel, as European cities tightened security over fears of a Paris-style terror attack. 

The Met Police confirmed the occasion was one of two events, along with Notting Hill Carnival, in which there was no holiday entitlement.

Force spokesman Superintendent Jo Edwards said the extra officers were for reassurance and the event was 'successful'.

She said: 'Our officers worked alongside stewards to support their operation and help people to get in and out of the event area safely and efficiently.

'Although the celebrations have drawn to a close, officers continue to work through the night to facilitate the clean up operation and bring the area back to normality in time for the New Year's Day parade.'

Today, more than 8,500 performers representing 20 countries will take part in the annual New Year's Day parade through London, again amid a large security operation. 

The event, which includes marching bands, cheerleaders, clowns and acrobats, kicks off in Piccadilly and finishes in Parliament Square, taking in Lower Regent Street, Pall Mall, Trafalgar Square and Whitehall. 

In Munich, German authorities declared a major terror alert over fears of an ISIS terror attack.

A foreign intelligence service had warned that between five and seven suicide bombers from the terror group had been planning on attacking the southern German city.

Two railway stations - Munich's main station and the Pasing station - were evacuated after indications of a planned attack which would target party-goers in the city. 

A police spokesperson said that they had ‘reliable information’ that a group was planning to act as festivities were well under way on New Year’s Eve. 

‘Actual lead that in #Munich a terror attack is planned. Please avoid crowd gatherings as well as the central train station and the Pasing train station,’ read the tweet.

Another tweet from the police read: ‘We note explicitly once again that we take the threat very seriously. Please remain alert.’

Across Europe, capital cities were on high security alert, with Brussels and Paris both scrapping fireworks for New Year's celebrations. 

In Berlin, the police presence was stepped up at the Brandenburg Gate, where hundreds of thousands of people gathered for festivities. All large bags and backpacks were banned from the site of the huge street party.

Major security operations involving thousands of police were in place in other cities, including Sydney, Bangkok, Delhi and New York.

Belgian police held a further six people suspected of plotting a New Year's Eve attack in Brussels. One was also charged with offences linked to the attacks on the French capital.