Highly spatially resolved mixing ratios of benzene and toluene, nitrogen oxides (NO<inf>x</inf>) and ozone (O<inf>3</inf>) were measured in the atmospheric boundary layer above Greater London during the period 24 June to 9 July 2013 using a Dornier 228 aircraft. Toluene and benzene were determined in situ using a proton transfer reaction mass spectrometer (PTR-MS), NO<inf>x</inf> by dual-channel NO<inf>x</inf> chemiluminescence and O<inf>3</inf> mixing ratios by UV absorption. Average mixing ratios observed over inner London at 360 ± 10 m a.g.l. were 0.20 ± 0.05, 0.28 ± 0.07, 13.2 ± 8.6, 21.0 ± 7.3 and 34.3 ± 15.2 ppbv for benzene, toluene, NO, NO<inf>2</inf> and NO<inf>x</inf> respectively. Linear regression analysis between NO<inf>2</inf>, benzene and toluene mixing ratios yields a strong covariance, indicating that these compounds predominantly share the same or co-located sources within the city. Average mixing ratios measured at 360 ± 10 m a.g.l. over outer London were always lower than over inner London. Where traffic densities were highest, the toluene / benzene (T / B) concentration ratios were highest (average of 1.8 ± 0.5 ppbv ppbv^-1), indicative of strong local sources. Daytime maxima in NO<inf>x</inf>, benzene and toluene mixing ratios were observed in the morning (∼ 40 ppbv NO<inf>x</inf>, ∼ 350 pptv toluene and ∼ 200 pptv benzene) and in the mid-afternoon for ozone (∼ 40 ppbv O<inf>3</inf>), all at 360 ± 10 m a.g.l.