The message in the letter to immigrant communities in Belfast could not be starker or more brutal. "Get out of our Queen's country before our bonfire night and parade day," it declared.
Emblazoned with a skull, it descended into a mixture of the semi-literate and the directly threatening with the warning: "Other than your building will be blown up."
The leaflet was delivered to centres in Belfast representing the city's Islamic, Indian and Polish communities, in advance of this weekend's high point of the loyalist marching season.
It has clearly generated worries among those communities, since all three of the centres would not comment on the threat.
But Patrick Yu, who heads the Northern Ireland Council for Ethnic Minorities, said the leaflets were designed to threaten and frighten, adding: "It really is more about trying to reignite the issue."
Just last month more than one hundred Romanians were flown out of Northern Ireland following a wave of attacks on their south Belfast homes in an episode which received worldwide publicity.
Although the letter is marked "Combat 18" and bears loyalist slogans, the authorities do not believe that any local or outside organisation is behind this threat or other racist attacks.
The belief is that both the attacks on Romanians and the general pattern of incidents are largely the work of racist individuals, mostly teenagers, in a primitive show of xenophobia and dislike of "outsiders."
But the major complication this weekend is that the annual 12th of July celebrations have been extended with several nights of festivities in prospect before the main Orange Order march takes place on Monday.
In the evenings loyalists gather round bonfires piled high with waste wood, unwanted furniture and old vehicle tyres. While most of these occasions pass off without serious incident, very large amounts of alcohol are consumed by many.
With large numbers of intoxicated teenagers and young men roaming the backstreets, the concern is that some of them might decide to target the homes of migrants for casual violence.
Racist incidents are already running at a rate of almost a thousand a year, mostly taking the form of attacks on migrants and their homes. Many of these live in or close to loyalist areas and are therefore vulnerable.
The police said yesterday: "Hate crimes and racially motivated attacks will not be tolerated by the Police Service of Northern Ireland. It is important to point out that it is a small group of people who are responsible for these incidents."
"Anyone out there who has information about anyone involved in the production or distribution of material which promotes or incites racism must bring that information forward."
The police and Orange Order this year launched a joint initiative aimed at reducing the consumption of alcohol, using the slogan "Enjoy the day - make sure it's not a blur."
They have urged people "to behave responsibly, to show tolerance, to avoid provocation or an inappropriate response to provocation."
July in Northern Ireland is sometimes described as a mad month when the blood can run high, with Catholic-Protestant tensions often increasing as the marching season reaches its climax.
In a familiar annual pattern, the past few weeks have seen sectarian attacks in and around Belfast and especially in County Antrim with both Protestant and Catholic premises targeted. Orange halls have been damaged in arson attacks while five Antrim Catholic churches were this week attacked with paint bombs.
All but a handful of Catholic families now remain in the village of Ahoghill, which has seen regular outbreaks of sectarian violence.
Antrim Protestant clergyman the Rev Robert Coulter said of those responsible: "These are mindless thugs who, it must be emphasised, are acting alone. This type of sectarian vandalism - be it Protestants attacking Catholic churches, or Catholics attacking Orange halls - will find no support within any community."
Against such a background the risk is that migrant homes may present an easy and tempting target to young drunks. At court proceedings arising from previous July incidents defendants were said to have been "out of their heads" after days and nights of drinking.
The fact that racist attacks now take place at a rate of almost a thousand a year seems to indicate that they have become endemic. Due to the troubles, migration to Northern Ireland was for a long time comparatively rare.
But with the steady reduction of paramilitary violence a stream of immigrants has arrived from Poland, other European countries and further abroad in the last five years.
Almost from the start some of these new arrivals came under attack, producing claims that racism is the new sectarianism.
Official surveys have confirmed a significant level of local opposition to those moving in from abroad.
Asked in a survey if Eastern Europeans were acceptable as residents in their local area, 18 per cent of respondents said no. This figure was even higher for members of the Islamic faith: 31 per cent said these were unacceptable.Reuse content