How many people speak Turkish in London?

A new report ordered by Mayor Boris Johnson on this subject has been prepared, and the conclusion is:...unknown! However, it does have some other interesting findings that I'll sum up here.

-The report was 52 pages long and on Turks, Cypriot Turks and Kurds.
-The Turkish-speaking population is unknown, but Cypriot Turks are more well integrated and have a better economic position than Turks and Kurds.
-One reason why the exact number is hard to know is that these groups will often mark themselves down on surveys in the "white/caucasian, white English and others" group.
-Places in London with large numbers of Turks and Cypriot Turks are Harringey, Hackney, Islington, Waltham Forest and Enfield.
-London is the place where most Turks and Cypriot Turks live in the country - 60% of Cypriot Turks born in Cyprus and 74% of Turks born in Turkey live in London.
-The Turkish and Kurdish population is younger than that of the Turkish Cypriot population.
-Turks and Kurds have a low
-Most Turks, Cypriot Turks and Kurds living in Londan work in restaurants, cafés and supermarkets, taxi companies, jewelers, clothing and import-export companies, and the unemployment rate among Turks and Kurds is double that of the unemployment rate in London.
-Education and health is also lower than the average.

The reason Johnson commissioned this report was to get a better idea as to how to improve health/education/etc. among minorities in London. Johnson's great-grandfather was also Turkish so he has a bit of personal interest there as well.

Also note the numbers from the 2001 census:

In the 2001 Census, nearly 52,000 people in London identified themselves as Turkish (37,827) or Turkish Cypriot (14,074). A further 7,360 stated they were Cypriot, without specifying whether they were Greek Cypriot or Turkish Cypriot. There were 9,659 people in London who identified themselves as Kurdish. The Census figures are considerably lower than estimates given by other local surveys and studies.

Wikipedia also has a page on the subject.