It has been nicknamed the Bangkok of the Baltic for its mix of cheap beer and sex clubs that attract thousands of British revellers every week.

But the mayor of the Latvian capital of Riga has called time on the hordes of invaders. In an outspoken attack, Nils Usakovs blames drunken British tourists for ruining his city's reputation and putting off other potential tourists.

Mr Usakovs is hoping to attract a wider range of visitors to the picturesque city which he believes could become "a little Las Vegas".

It has emerged authorities in Riga contacted the Foreign Office asking for help to deal with the Brits at the end of last year and British police have visited to try to assist their Latvian counterparts.

"The only problem is that we have a large share of those British tourists," said Mr Usakovs.

"If we also had other tourists, then British visitors who p*** about all the time would not be as noticeable. Let's not be politically correct - unfortunately, this is their speciality," he added.

Riga is one of a handful of central and eastern European cities popular with stag or hen parties as low-cost airlines have made them more accessible. Ryanair puts on two direct flights a week to Riga from Prestwick.

But rowdy parties in search of cheap beer are deterring a wider range of visitors.

A major sore point has been tourists who urinate on central Riga's imposing Freedom Monument, a symbol of Latvia's struggle against centuries of foreign domination.

Visitors have regularly been arrested and fined for relieving themselves on the 138ft-high monument, or climbing on it naked to pose for pictures.

Riga should try to attract more civilised visitors from other countries, Mr Usakovs added.

His comments came as two British citizens are to face trial in Riga after being extradited.

Matthew Neale, 35, and David Birkinshaw, 33, from Derbyshire are accused of assaulting a police officer in a nightclub while part of a stag party in June 2008.

If found guilty, they could face a prison sentence of up to seven years.

It was following the attack that the Independent Union of Police Officers in Latvia proposed to invite British policemen to Latvia for joint patrols of the streets of Riga.

In May 2008, a 32-year-old Briton was fined for roaming naked through the streets of Riga Old Town. Three months earlier, a 34-year-old London man became the first to be locked up rather than fined for urinating on the Freedom Monument.

The previous year, a kilt-wearing 23-year-old Scot was detained after climbing on to the monument and exposing himself.

Interior minister Mareks Seglins described those who relieve themselves on the monument at the time as "those English pigs".

President Valdis Zatlers rebuked Mr Seglins, saying that, while foreigners should obey the law, Latvian officials should not resort to name-calling.

Following Riga's appeal to the Foreign Office, two officers responsible for policing Cardiff, another city popular with stag revellers, were invited to assist them last January.

While Riga draws its share of thrill-seeking tourists, it also brings in tourists attracted by rows of buildings developed during the art nouveau period at the end of the nineteenth century and start of the twentieth when Latvia was part of the Russian empire.

Riga's Old Town has been included in the United Nations Educational, Scientific and Cultural Organisation's World Heritage list.

It is this contradiction that prompted the launch of a campaign against sex tourism in 2007, saying the city had become a Baltic Bangkok.

The authorities in Riga have made several attempts to tackle problems caused by large groups of young male holidaymakers including setting up a special English-language tourist hotline.

The British Embassy in Riga publishes on its website tips for Britons visiting the city. Advice includes "Do not urinate in public" and "Respect others, do not use abusive language."

The country's economy became the fastest-growing in the European Union helped by the number of tourists visiting Latvia, following its entry into the EU in 2004. Figures show that visitor numbers had gone up by 24% in the year that followed - boosted by Riga's reputation as a party city.