  We performed simultaneous observations in 3 bands (UBV) of the flickering
variability of the recurrent novae RS Oph and T CrB at quiescence. Using new
and published data, we compare the colours of the flickering in cataclysmic
variables and symbiotic recurrent novae. We find a difference between the
colours of the flickering source in these two types of accreting white dwarfs.
The detected difference is highly significant with $ p-value \approx 2 \times
10^{-6}$ for the distributions of $(U-B)_0$ colour and $p \approx 3 \times
10^{-5}$ on (U-B) versus (B-V) diagram. The possible physical reasons are
briefly discussed. The data are available upon request from the authors.
