Hopes for the UK wheat took a further knock when leading consultants downgraded their estimates for both the quality and quantity of the crop, warning that the yield could register a 20-year low.

As farmers harvested the last fields, in Scotland, Adas analysts cut to 6.9-7.2 tonnes per hectare their forecast for the yield of the European Union's third-ranked wheat harvest.

"Additional yield information from Scotland and confirmation of yields from other areas have resulted in a downward revision of estimated average UK yield," the consultancy said, cutting its estimate from 7.1-7.4 tonnes per hectare

"Yields from light land are better than normal," with sandier soils proving an advantage during the UK's wettest summer for a century, "but they account for a relatively small proportion of the total crop area".

20-year low?

Indeed, Adas signalled that a final figure below 2001's poor result of 7.1 tonnes per hectare looked on the cards – leaving the UK looking at its worst yield since the figure of about 6.7 tonnes per hectare registered in 1992.

Low specific weights – a measure of the weight of grain per given volume, which assesses levels of shrivelled kernels – "mean that yield estimates based on crop volume often overestimate the true yield.

"So the final UK average yield may be at the lower end of the range," the consultancy said in a report for the HGCA crop bureau.

The assessment tallies with a forecast last week from Paris-based Strategie Grains of a UK yield of 6.95 tonnes per hectare.

The crop was damaged both by heavy rains from late spring which hampered development and slowed harvest, leaving grains to deteriorate in the field, after drought earlier in the season.

'Main quality issue'

Furthermore, Adas was downbeat over quality too, saying the specific weight had been "typically below 70 kilogrammes per hectolitre", hardening ideas that, on this score, the crop is on course to record its worst result on records going back to 1977.

"Specific weight remains the main quality issue for the wheat crop as a whole."

However, while Hagberg falling numbers, a measure of sprouting which uses up a grain's reserves, were declining, on this score "most milling crops in the northern regions are still achieving specification".

Grain protein levels were "good", at an average of 12.7%.