Russians and citizens from the Baltic states have congregated in Stratford, where several new delis and shops have sprung up to meet their needs, reports estate agent Richard Everitt of Winkworth. Many have come to fill the jobs Londoners no longer want, such as cleaning offices, or in the building trade. Some aim to stay for good, renting flats for themselves and their families while they retrain.
"They are all qualified in their own countries," Everitt says. "One of our tenants is a qualified doctor working as a painter and decorator while he takes the seven exams he needs to pass to practice medicine here."
Stratford became popular because of cheap rents and good transport links to jobs in the City and Canary Wharf, but the success of the Olympic bid has already pushed prices up. It is too early to see if residential rents will go up as construction starts, but costs for premises such as the shops and restaurants that serve the Eastern European community have already gone up, Everitt says.
It is possible that the enclave in Stratford may be forced out even before it has become established. If the migrants move en masse, they will probably go further out, or possibly south to New Cross or Deptford.
If the area round your buy-to-let property has an influx of a specific nationality or culture, it pays to ensure that the property meets their special requirements. For example, orthodox Jews need two sinks and two fridges for kosher food preparation, and Muslims like to have two large reception rooms so men and women can meet separately.
The other issue for a landlord in catering for new arrivals is the difficulty of getting references. "Foreign tenants have to have been here for three years before they can get a rent guarantee, so we usually ask for three to six months' rent up front, especially if they have no references outside work," Everitt says.
Rent-protection insurance is also available from such companies as Letsure (www.letsure.co.uk), which also have services that find out as much as possible about a new tenant before handing over the keys. This does not come cheap, at around 3.5 per cent of the monthly rent, but investors using borrowed money may start to lose serious sums if the rent stops and costly legal action is necessary to recover the property.
Another issue is the practice of tenants sleeping up to four to a bedroom to save on rent. This overcrowding may have implications for wear and tear, and is difficult to monitor.
In north London, the borders of Stoke Newington and Stamford Hill have seen an influx of Poles since that country's accession to the EU. Long-term Stoke Newington resident Mark Olbrys of Cluttons is himself half-Polish and suddenly finds himself surrounded by his father's compatriots. "Poles are moving massively into what was traditionally a Jewish and Greek Cypriot area," he says. The large number of substantial family homes is the draw in the area.
There has been an enclave of Poles in exile in Kensington since the Second World War, when former soldiers and RAF pilots found it impossible to return when the Red Army moved in to their homeland. They gathered round clubs such as the Polish Air Force Association in Collingham Gardens and the ineffable Daquise restaurant next to South Ken station.
The invisible immigrants are the Czechs, according to David Frous of the Embassy of the Czech Republic. "It is not a great part of the Czech nature to gather in close communities," he says. "We try to merge into the environment."
That said, there are long-standing concentrations of Czechs in Hammersmith and Hampstead. The Czechoslovak National House (actually a pub and restaurant) in West End Lane, Hampstead, has been a magnet for homesick Czechs (and Slovaks) since the Second World War, Frous says.