Joy Lo Dico: Now the middle classes are being squeezed out

London estate agents are hiring French-speaking staff to prepare for a flood of well-heeled Gallic buyers

As François Hollande ascends to the Elysée Palace with a pledge to raise the top rate of tax to 75 per cent, top-notch London estate agents are preparing for a new flood of enquiries from our well-heeled Gallic neighbours looking for a way out. Advertisements have been appearing for French-speaking staff and one agency, Douglas & Gordon, is opening a dedicated French branch in South Kensington this summer.

Add to this another spasm of émigrés from the renewed political turmoil in Greece, and the continued popularity of our capital for the Russian and, increasingly, Chinese rich and super-rich, and London, in sharp contrast to the rest of the UK, has become one of the most expensive melting pots in the world.

Immigration to London is an old story. Over the past 60 years, it has brought hundreds of thousands from the Caribbean, Bangladesh, Poland and, most recently, Somalia. However, those travellers arrived largely on the doorstep of the working and lower middle classes, who felt the discomforts – the shortages in housing and school places, their neighbourhoods changing and the sense that their jobs were under threat from cheaper labour. It was a problem that the more prosperous, who prided themselves on open minds and open doors when it came to the foreigners who joined the working class, could read about in the newspapers without any significant impact on their own lives. But it may now be the time when the middle classes begin to feel those discomforts, too.

The capital now has an estimated 300,000 French residents, and 100,000 Russians, many of them professionals. Hard stats will come in the census results in September but the evidence of the wealth they have brought with them is already obvious in the housing market. While prices in the rest of Britain sink, those in London continue to rise. The pinnacle of the growth is Knightsbridge, a Russian hotspot, while South Kensington, with its abundance of French delicatessens and cafés, is sometimes referred to as the 21st arrondissement. Eight-five per cent of London super-prime estate – property worth over £10m – is now held by overseas buyers, with heavy investment from Greek buyers in 2010. And the demand for expensive properties, above the £2m mark, has radiated from the centre out to middle-class heartlands such as Battersea and Queen's Park. Pleasant but unremarkable districts on the fringes of central London, they have now gone beyond the reach of many families with merely decent incomes, such as civil servants, academics and small business owners.

Skirmishes over jobs have yet to be voiced. Many of the immigrants are their own bosses or bring their own niche jobs; French financiers have a long-standing specialism in equity derivatives and investment banks expand for them. Their Russian equivalents are the link between the City and Moscow money. But, in education, it is more of a zero sum game. Not for good state schools but for the equally hard-fought battle for private places against well-tutored Russian and Chinese children. There has been another 5 per cent increase in pupils with parents based overseas in British independent schools, following the same rise last year. One mother recently noted to me, pointedly, that outside a top west London girls' school she passed daily, there was a line of chauffeur-driven cars waiting to pick up "the little princesses". This of course, is far from real hardship of the sort felt in the poorer parts of London. But it pinches enough that some of the chattering classes have started to ask what is in it for them.

There's an easy upside to the new flocks of foreigners. The capital is booming with demand for smart restaurants, interior decorators, and handbags, as well as our financial and legal services. The downside is that professional Londoners, many of them children of immigrants, are finding their aspirations capped by their foreign peers. Where the stresses of previous immigration had been at the bottom of society's pyramid, the new wealth has arrived from above and exerts a downward pressure.

One flashpoint of resentment is tax. The "benefit scroungers" headlines are being supplanted by those outing non-domiciles. In last month's Sunday Times Rich List, only two of the 10 people at the top claimed British nationality. Nor does owning London property necessarily tie you into British society. The most notorious example of this is One Hyde Park, the Candy brothers' development in Knightsbridge, where apartments start at £3.6m and rise to £136m. As of November, only nine had been registered for council tax, five of those as second homes. The Candy brothers also advised purchasers on avoiding stamp duty.

The super-rich are exotic birds who may well fly away when the political climate here or back home changes. Hundreds of thousands of the more moderately wealthy have embedded themselves in London life, and will have invested in our society. But, with the housing market still bubbling, high demand for private schools and the increased competition in the top jobs market, there must come a point when Londoners look at Queen's Park and Battersea, let alone the high-class ghettoes and wonder why they can't get in.