Do Galaxies Form at High Redshift?

We show that the numbers of colour selected U-band 'drop-out' galaxies on the Hubble and Herschel Deep Fields is consistent with the predictions of simple Pure Luminosity Evolution models out to z similar to 3. At z similar to 4 the number of bright galaxies, selected by B-band 'drop-out' is also consistent, but there appears to be a deficit of sub-L* galaxies compared to the models. The selection of z similar to 6 objects by, R-band 'drop-out' is discussed, and significant number of potential candidates shown to exist on the Herschel Deep Field, suggesting that the epoch of galaxies formation, at least for luminous galaxies, was at least z similar to 6.