Anastasia Ploshkina is the director of the show and she describes the song here:
In researching their show based on Russian folk music and dance, Koleso have uncovered an extraordinary ancient and poignant link between the ordinary people of Russia and England.

Deep in the Russian countryside in a very remote village, they found a very old woman called Olga Sergeeva. After her daughter died, tragically, Olga Sergeeva never spoke another word for 10 years and then amazingly she began to sing, and sing ancient Russian songs passed down to her through the generations with a tender mellow timbre that moved any who heard it to tears. Koleso were intrigued by one of her songs, "Skagi-skagi". After much research, they found extraordinarily that this song from the remote heart of Russia was based on the English song In London City which they now include in their show."

http://www.youtube.com/watch?v=oius1eEpghU