Stubble burning has been banned for a good few years now, about 15 I think.
We used to practise it on the farm as a very effective way of removing stubble prior to cultivation, the resultant ash also had a value.
It was great fun to do but you had to be very very careful. Chose a dry day with little wind. Plough a margin/fire break around the perimeter of the field to prevent the hedges being caught. Have a water bowser on hand incase the fire jumped the margin and have plenty of hands ready to help if needed.
If you get it right you can burn a 20 acre field in a matter of minutes and have no problems at all, get it wrong and I have seen/heard of hedges, barns, tractors, pick up trucks, etc all going up in smoke.
The worst accident we had was on a very hot day burning barley stubble in a field where there are 4 electricity poles that bring the 3 phase supply onto the farm from the grid. These poles are soaked in tar/creosote to prolong their life. Normally we did not plough around them to form a fire break but on that day we should have as the tar was weeping out of the poles due to the heat.
We ended up with 4 giant match sticks blazing away, trying to put them out proved hard with limited water so we had to call the fire brigade whoi laughed their socks off when they arrived.
The electricity company were none too pleased though!
Oops!
Jerry