The firm said that with forecast accuracy as close as 0.6% for the fleet flagship lower medium sector, it is confident that Gold Book represents the most demonstrably reliable independent forecasting tool in the industry.

Dylan Setterfield, CAP’s senior forecasting editor, said: ‘Key to the Gold Book forecast methodology is the differentiation between age, sector and fuel type instead of the more typical “one size fits all’ approach that treats the market as a single entity.

‘We also changed all elements of the calculation to reflect the true expected evolution of used values, rather than relying on artificial depreciation curves.

‘We are therefore delighted to see that the actual market deviated from our forecasts for 2014 by only 1.6% overall and as little as 0.6% for the lower medium sector, which is so important for fleets to forecast as accurately as possible.’

Looking ahead to the Gold Book view of 2015, year on year market deflation is expected to increase from 2.8% this year to six per cent next year. This compares with typical historical figures ranging 3 and 5% per annum, depending on vehicle sector.  It is therefore slightly more than would be expected from normal lifecycle factors.

This represents a genuine market view and is not distorted by the impact of new model introductions, which are accounted for separately in the Gold Book methodology.

Describing the market shift in 2015 as ‘from benign to deflationary’, Setterfield says the change is largely influenced by on-going increases in used car supply coupled with flat or only slightly positive demand.

He said: ‘In summary, 2015 will be more deflationary than the last three years as supply continues to increase. However, little or no reduction in demand – compared with this year – will mean no repeat of the severe market conditions we saw in 2008.’