A British tourist who urinated on one of Latvia's most revered monuments was made an example of by the Baltic state yesterday and sentenced to five days in custody.

Increasing numbers of foreigners are abusing the Freedom Monument, or Brivibas Piemineklis, which was erected in Riga in 1935 in memory of those who fought for Latvian independence. The 42-metre-high statue is seen as an important symbol of the state's sovereignty and is a focal point for public gatherings.

But now, stag parties and rowdy gatherings in the area have led to a spate of incidents at the monument. Yesterday, the Latvian Interior Minister, Mareks Seglins, described the principle culprits as "those English pigs".

The latest of the alleged perpetrators, a 34-year-old man from London, is the first to be locked up rather than fined after urinating on the monument, The Baltic Times newspaper said. According to the report, the man unusually pleaded not guilty, claiming his trousers accidentally fell down "in a moment of horseplay" when he was on the monument's steps, which can be accessed from the street.

The incident is the latest to have upset the Latvian authorities. Last year, a 23-year-old Scot was detained after clambering on to the monument and exposing himself by pulling up his kilt.

The newspaper added: "The perpetrators are widely perceived to be British and Irish stag party-goers who become inebriated and then choose to empty their bloated bladders in the shadows of the Freedom Monument, unaware of both its historical significance and the fact that police keep a close watch on it day and night."

The jail sentence comes after Riga's Mayor, Janis Birks, voiced concern at the leniency shown by the authorities. And the National Police Chief, Aldis Lieljuksis, has suggested that a 15-day custodial sentence would be appropriate.

Other nationalities including Poles and Norwegians have also been apprehended on or near the Freedom Monument for a variety of reasons, including attempting to scale the monument itself. In the latest incident, "the court took into account the fact that [the accused] was under the influence of alcohol at the time of the offense," The Baltic Times said.

The British embassy in Riga instructs visitors: "Do not urinate in public – always use a toilet. It is not worth going to jail or paying an expensive fine."