There are a lot of scare stories in the press at the moment claiming that if there is a No Deal Brexit, the supermarket shelves will become bare and the country will run out of fuel in two weeks.
Never mind that even in WW2, when Britain was being besieged by U-boats and the Blitz, people had adequate food to eat.
So what plans have been made for a No Deal Brexit?
Most of the planning appears to be being done by the private sector. In particular all the ports are expanding because they envisage increased shipping coming in from the rest of the world outside the EU:
Britain's largest container port, Felixstowe started expansion in Jan 2018, which is scheduled to be completed in Jan 2019:
https://www.porttechnology.org/news/expansion_begins_at_uks_largest_port
Oct 2016: the port of Southampton acquired new land for expansion:
https://www.bbc.co.uk/news/uk-england-hampshire-37790178
Jan 2018 the port of Southampton acquired more additional land for expansion:
https://www.bbc.co.uk/news/uk-england-hampshire-42845101
The port of Holyhead is expanding:
https://www.gov.uk/government/publications/port-of-holyhead-expansion
The port of liverpool is expanding it's new deep water terminal which opened in 2016:
The port of Blyth secured money for expansion:
http://portofblyth.co.uk/new-banking-facility-enables-port-expansion/
The port of Great Yarmouth is expaning:
http://www.edp24.co.uk/business/30m-port-investment-indicates-commitment-to-offshore-wind-1-5290037
The container terminals on the Humber at Hull and Immingham have invested £50 million in expanding:
https://www.ft.com/content/35463ce8-162e-11e7-80f4-13e067d5072c
In addition Bristol is planning a £600m deep-sea terminal and Dover is spending £250m on its western docks to improve freight facilities.
What is the govt doing?
They stumped up £6.1 billion for motorway expansion in June 2017:
And they've put £100 million into a supply part at Sunderland to feed the Nissan car factory. The supply park won planning permission in May 2018:
https://www.theengineer.co.uk/manufacturing-park/
The civil service is also planning for No Deal Brexit and making plans to allow the military to fly food supplies across the country if necessary:
Britain doesn't get oil from Europe, instead it gets it from it's own oilfields in the North Sea and from Norway. The same goes for gas - it either comes from the North Sea, from Norway, or friom LNG terminals that take gas from Qatar and the USA, both of which will be unaffected by Brexit.
The private sector is starting to switch supply chains
JD Wetherspoons the pub chain consisting of 880 pubs announced that it would be replacing EU-sourced drinks with UK drinks starting from 9th July:
It's a smart move - it means they will be protected from supply delays at the ports and tariffs in the event of a No Deal Brexit.
The pharmaceutical company Merck is plannng to stockpile six months drugs in the UK in the event of Brexit and also to build more time in it's supply chain:
Conclusion
I expect most private companies are waiting for the outcome of the June summit with the EU before they pull the trigger and switch suppliers. If most of them do what JD Wetherspoons is doing, then the volume of goods coming in from Europe will start to decrease, and that by itself will offset any delays in processing customs.
I wouldn't be surprised if households stocked up in advance too, "just in case".
Brexit is a bit like the Millenium Bug - a known event happening on a known date with the private sector doing most of the work to get ready.