The use of polytunnels - long plastic tunnels - by the British soft fruits farming industry is under the microscope at a court hearing.
Polytunnels are used to grow frost-sensitive fruit
The operator of a farm near Godalming, in Surrey, wants the High Court to overturn a ruling that the tunnels need planning permission.
The Hall Hunter Partnership's lawyer said they were "an agricultural use of land" - and exempt from planning rules.
Opponents believe the polytunnels are "a blight on the landscape".
Hall Hunter bought the 469-acre Tuesley Farm in 2003 and has grown strawberries, raspberries and blackberries there.
Polytunnels were put on the land between March and November 2004, but Waverley Borough Council issued planning enforcement notices requiring the partnership to stop erecting them.
A 13-day planning inquiry ended with an inspector upholding the council's decision.
'Vital to agriculture'
Timothy Straker QC, for the partnership, said that polytunnels were erected according to crop rotation and therefore could not be classed as permanent buildings covered by the 1990 Town and Country Planning Act.
"Polytunnels can properly be said to be vital to agriculture," Mr Straker told the court.
The tunnels extend the growing season and the soft fruits farming industry argues that production would be harmed if planning laws restricted their use.
A campaign group set up by more than 80 families living near Tuesley Farm have condemned the polytunnels as being part of "an enormous industrial farming operation" on green belt land.
The hearing is expected to conclude on Friday.