Average earnings in the Royal Borough rose by nearly £700 in four years - but it represented a 13.2 per cent drop in real terms.
According to figures released by Office for National Statistics, for the GMB union, the mean gross income was £43,113 in November 2012 compared to £42,436 in April 2008.
Slough increased from £25,469 in 2008 to £26,187 in 2012.
Other nearby authorities dropped with Bracknell Forest falling from £31,597 to £31,579 and Buckinghamshire to £36,713 from £37,118.
Average earnings across the UK rose to £26,664 from £26,137 a drop of 12.8 per cent in real terms taking into account the costs of goods and services.
Top Ten Articles
The Met Office has issued a yellow alert for Windsor and Maidenhead, Slough and Wokingham, warning that rain moving eastwards across the south of the country may turn to snow in some places.