Police are investigating an incident in which 250 bales of straw were set on fire in a field off the A413 between Whitchurch and Winslow on August 7.
The incident which happened just before 9pm is being treated as a ‘potential arson’.
The blaze caused the A413 to be closed between the Dunton Road and Oving Road turns for almost 24 hours.
Five fire crews attended the incident and there were at the scene for more than 24 hours to bring the blaze under control.
No arrests have been made and anyone with information is asked to call the non-emergency police number on 101 quoting reference 43180242254.