WTO restrictions on subsidies to farmers & fishing
Maybe Leavers will demand we leave WTO next 
Dmitry Grozoubinski@DmitryOpines
2/ So right off the bat.
There are some types of agricultural subsidy that are WTO legal in any amount.
There are some types of agricultural subsidy that are WTO legal in limited amounts.
There are a few types of agricultural subsidy that are WTO illegal.
3/ The most obvious way to use government subsidies to support farmers locked out of the EU market by No-Deal
would be to give them to farmers exporting to the EU, to help them offset the new tariffs by lowering prices.
This is an EXPORT SUBSIDY and is definitely illegal
4/ The second most obvious way would be to use government subsidies to support farmers who previously exported to the EU, based on how much they did so.
This is still (lawyers jump in here) an EXPORT SUBSIDY and illegal.
5/ That doesn't mean Mr Hunt can't spend billions of pounds to help farmers.
It just means that when he's spending that money, he can't use past or present export performance as a test for who gets it.
So to support lamb exporters, he'd have to support all lamb producers.
6/ Fisheries is a slightly different story, because it's covered under a different WTO Agreement (Agreement on Subsidies and Countervailing Measures or "SCM").
This agreement is a bit tighter with subsidies than the Agreement on Agriculture.
7/ Under the SCM, not only are export subsidies illegal
but if you provide sector or industry specific subsidies and another market feels those subsidies are impacting their market,
they can conduct an investigation and impose a "Counterveiling Measure."
What's that?
8/ It's a targeted tariff.
They are allowed to raise their tariffs on that product from you (just you) even beyond the maximum tariffs laid out in their WTO Goods Schedule.
So they are basically allowed to use tariffs to 'cancel out' your subsidy.
9/ None of this means there is no way for Mr Hunt to support farmers and fishermen and women impacted by No-Deal Brexit.
For the record, I think there's almost a moral imperative to do so,
both for the farmers and fishermen and women themselves and for their communities.
....
10/ What it does mean is that the UK has obligations not to provide such support in some of the most obvious and cost effective ways,
and that one can't simply use subsidies to "brute force" industry's way through EU's tariffs.
/end