We report for the first time on the magnitude of the intrinsic [ Fe/H ] spread among ten old globular clusters ( GCs ) of the Large Magellanic Cloud ( LMC ) .
Such spreads are merely observed in approximately five per cent of the Milky Way GCs and recently gained more attention in theoretical models of GC evolution .
We derived metallicities with a typical precision of 0.05 dex \leq \sigma { [ Fe / H ] } \leq 0.20 dex for an average of 14 red giant branch stars per GC from Strömgren photometry .
The respective , metallicity-sensitive indices have been calibrated to precise and accurate high-dispersion spectroscopy .
For all clusters we found null [ Fe/H ] spreads with a typical uncertainty of 0.04 dex , with the possible exception of NGC 1786 that shows an intrinsic dispersion of 0.07 \pm 0.04 dex .
The mean , observed standard deviation of the derived metallicities for nearly 40 per cent of our GC sample amounted to smaller than 0.05 dex .
At present , we can not exclude that the remaining GCs also have intrinsic Fe-abundance variations in excess of 0.05 dex , but in order to significantly detect those , the measurement errors on individual [ Fe/H ] -values would need to be lowered to the 0.03–0.07 dex level .
These findings suggest , along with those from ages and light-element abundances , that the LMC GCs studied here are alike to the majority of Galactic GCs .