We present statistically significant detections at 850 \mu m of the Lyman Break Galaxy ( LBG ) population at z \approx 3 , 4 and 5 using data from the Submillimetre Common User Bolometer Array 2 ( SCUBA–2 ) Cosmology Legacy Survey ( S2CLS ) in the United Kingdom Infrared Deep Sky Survey “ Ultra Deep Survey ” ( UKIDSS-UDS ) field . We employ a stacking technique to probe beneath the survey limit to measure the average 850 \mu m flux density of LBGs at z \approx 3 , 4 , and 5 with typical ultraviolet luminosities of L _ { 1700 } \approx 10 ^ { 29 } erg s ^ { -1 } Hz ^ { -1 } . We measure 850 \mu m flux densities of ( 0.25 \pm 0.03 ) , ( 0.41 \pm 0.06 ) , and ( 0.88 \pm 0.23 ) mJy respectively , and find that they contribute at most 20 per cent to the cosmic far-infrared background at 850 \mu m. Fitting an appropriate range of spectral energy distributions to the z \sim 3 , 4 , and 5 LBG stacked 24–850 \mu m fluxes , we derive infrared ( IR ) luminosities of L _ { \mathrm { 8 - 1000 \mu m } } \approx 3.2 , 5.5 , and 11.0 \times 10 ^ { 11 } L _ { \odot } ( corresponding to star formation rates of \approx 50 –200 M _ { \odot } yr ^ { -1 } ) respectively . We find that the evolution in the IR luminosity density of LBGs is broadly consistent with model predictions for the expected contribution of luminous IR galaxy ( LIRG ) to ultraluminous IR galaxy ( ULIRG ) type systems at these epochs . We also see a strong positive correlation between stellar mass and IR luminosity . Our data are consistent with the main sequence of star formation showing little or no evolution from z = 3 to 5 . We have also confirmed that , for a fixed mass , the reddest LBGs ( UV slope \beta \rightarrow 0 ) are indeed redder due to dust extinction , with SFR ( IR ) /SFR ( UV ) increasing by approximately an order of magnitude over -2 < \beta < 0 such that SFR ( IR ) /SFR ( UV ) \sim 20 for the reddest LBGs . Furthermore , the most massive LBGs also tend to have higher obscured-to-unobscured ratio , hinting at a variation in the obscuration properties across the mass range .