They have been running a Monday fair since 2010, and Rachel Everett, IACF's operations manager, said: "The one-day format is a great success but we wanted to create a fair that is more accessible to members of the public who can't always take off time in the week - by going on a Friday and a Saturday we hope to offer the best of both worlds to buyers and stallholders alike."
The trial fair at this Lincolnshire site is on Friday and Saturday, July 11 and 12.
The one-day Swinderby fair, which fills the gap between each of IACF's two-day fairs at Newark, was launched in 2010 and was swiftly followed during that year by a one-day Monday fair at Newbury racecourse.
Readers with longish memories will recall that in 2009 IACF had planned dates for a regular two-day event at the Swinderby site, newly acquired by the company after Swallow Fairs vacated this longstanding venue.
These clashed with Swallow's own calendar at the organisers' new venue, the Lincolnshire Showground. Back then, this controversial decision caused a certain amount of turf wars. In the event, this clash of dates was given the thumbs down by IACF stallholders and buyers and was scrapped in favour of a one-day fair at Swinderby. And so it came to pass.
The only other weekend fair in the IACF fair stable is their hugely popular three-day antiques and collectors' weekend event at Shepton Mallet which is a big hit with the trade and privates alike, particularly the latter. Running six times a year, it has proved a real stormer.
But with the acquisition of Nelson Events' Sunday fair at Alexandra Palace, with the first under the IACF banner on Sunday, September 14, IACF are maybe looking to balance their portfolio of fairs held during the week with more fairs which pull in a Saturday or Sunday crowd.