The UK, once one of the European Union's top wheat exporters, looks poised to be a net importer of the grain again this season, Gleadell said, citing a harvest which has "largely disappointed".
The UK began 2017-18 as a net importer, buying in 155,497 tonnes in July, compared with exports of 16,254 tonnes.
But while there is often such an imbalance early in the season, ahead of the onset of supplies from the domestic harvest, the trend of imports exceeding exports looks set to hold, for what would be the fourth time in the past six years
"It is evident that we will be a net importer again this season," the grain merchant said.
Historically, the UK has been a net wheat exporter, a position it ceded only once up to 2011-12, on data going back to 1995-96.
On average, it was a net exporter of 1.7m tonnes over those 17 seasons.
However, production of the grain has suffered from the historic wetness of 2012, which in curtailing autumn sowings depressed the 2013 harvest too, and more lately by the battle against black grass, which has prompted a shift to spring crops to create a longer window for applying pesticides.
Spring sowings continue to account for only a small proportion of overall UK wheat seedings.
Meanwhile, domestic demand has increased, thanks largely to the increased running rates of the Ensus and Vivergo ethanol plants, which have capacity for more than 1m tonnes of wheat a year.
Gleadell said it was working on the UK harvest coming in at 14.5m tonnes, or at the "top end" 15.0m tonnes.
"With crop often coming pretty wet off the field, one of the big questions is where the harvest ends up by the time is has lost a percentage through drying," Gleadell trader David Woodland told Agrimoney.com, although adding that yields have "largely disappointed".
Meanwhile, the merchant was working on the prospect of a "slight increase" year on year in consumption of wheat by ethanol plants, and a small reduction in milling use.
Furthermore, Mr Woodland flagged the weak level of stocks entering 2017-18, a hangover from an enthusiastic start to last season for exports, following on from a relatively weak harvest.
Indeed, he had expected the UK to prove an even larger net importer in July, given the tendency of many consumers to guarantee supplies through foreign purchases until they get a better idea of the quality and quantity of the domestic harvest.
However, the final trade balance will "depend to some extent on farmer retention", and the availability of wheat on the market, Mr Woodland said.
Furthermore, there remain questions over the relative popularity of grains in livestock rations, with barley "discounted heavily", at some £12-20 a tonne below feed wheat.
Indeed, at CRM AgriCommodities, James Bolesworth was sceptical over the prospect of the UK remaining a net wheat importer, thanks to the likelihood of feed mills turning to other grains, including importer corn.
"Typically, corn imported from the European Union is at a premium of about £10 a tonne to wheat," Mr Bolesworth said.
"However, at the moment the premium is at £2 a tonne, and last week corn fell into a discount, of about £2-3 a tonne."
Still, Mr Bolesworth acknowledged that UK wheat was "not competitively priced for export" at the moment, with the question of whether the country will be a net importer or exporter indeed a key once for pricing.
Gleadell also said that "UK wheat is not competitive for export", flagging the revival in sterling, which "seems underpinned after its recent rally".
Being a net importer allows for significantly higher pricing for domestic supplies, which have to exceed the price of rival foreign supplies plus shipping costs before they become uncompetitive.
Still, with the European Union as a whole enjoying a better harvest this year, and the Black Sea forecast to see record exports, Mr Woodland said he was advising farmers "to sell a bit, to go into the market when we do see a rally".