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High-resolution spectra for 24 SMC and Galactic B-type supergiants have beenanalysed to estimate the contributions of both macroturbulence and rotation tothe broadening of their metal lines. Two different methodologies areconsidered, viz. goodness-of-fit comparisons between observed and theoreticalline profiles and identifying zeros in the Fourier transforms of the observedprofiles. The advantages and limitations of the two methods are brieflydiscussed with the latter techniques being adopted for estimated projectedrotational velocities (\vsini) but the former being used to estimatemacroturbulent velocities. Only one SMC supergiant, SK 191, shows a significantdegree of rotational broadening (\vsini $\simeq$ 90 \kms). For the remainingtargets, the distribution of projected rotational velocities are similar inboth our Galactic and SMC samples with larger values being found at earlierspectral types. There is marginal evidence for the projected rotationalvelocities in the SMC being higher than those in the Galactic targets but anydifferences are only of the order of 5-10 \kms, whilst evolutionary modelspredict differences in this effective temperature range of typically 20 to 70\kms. The combined sample is consistent with a linear variation of projectedrotational velocity with effective temperature, which would imply rotationalvelocities for supergiants of 70 \kms at an effective temperature of 28 000 K(approximately B0 spectral type) decreasing to 32 \kms at 12 000 K (B8 spectraltype). For all targets, the macroturbulent broadening would appear to beconsistent with a Gaussian distribution (although other distributions cannot bediscounted) with an $\frac{1}{e}$ half-width varying from approximately 20 \kmsat B8 to 60 \kms at B0 spectral types.Comment: 4 figures, 8 pages, submitted to Astronomy and Astrophysic

B-type supergiants in the Small Magellanic Cloud: rotational velocities and implications for evolutionary models