Media playback is unsupported on your device Media caption No deal Brexit papers revealed by @politicalpics

It's good and sensible to plan.

If they weren't taking it seriously, as the government was very regularly criticised for failing to do, careering into a 'no deal' scenario would be pretty irresponsible, and planning properly for no deal has also been prized by Brexiteers as evidence that the PM might actually walk away if the offer on the table is simply not good enough.

A literal snapshot of some of that planning today has given a slice of insight into the kind of preparation that's taking place inside the Treasury, so called 'Operation Yellowhammer'.

As an intellectual exercise, none of this brief excerpt is completely surprising.

It demonstrates the political reality that in government there is concern about what might happen to the financial system, as well as transport, air and rail.

But it is still a message to government departments they should try to find cash to spend on "no deal" preparations from existing budgets, rather than the big cash pot that's been allocated so far.

That could give yet another reason for Brexiteers to get riled. But in this hot political climate, that's not hard to do. The Treasury officially won't comment on the leak.

Here is the text of the snap, captured by the sharp-eyed Westminster photographer @politicalpics:

HMT briefing - Operation Yellowhammer - 04 September 2018

Operation Yellowhammer: no deal contingency planning

Summary of issue

•This meeting will consider progress on the Government's plans for mitigating the immediate impacts of a No Deal Brexit.

•The Civil Contingencies Secretariat held a two-day workshop last week to review departments' plans, assumptions, interdependencies and next steps.

HMT objectives

1.Emphasise the importance of building XWH [cross Whitehall] communications architecture that can help maintain confidence in the event of contingency plans being triggered - particularly important for financial services.

2.Explain that departments should be raising Yellowhammer costs through the normal channels - through their spending teams for in-year pressures, and in their bids for 19/20 Brexit allocations for spending that year. Their first call should be internal prioritisation.

3.Reaffirm the need for consistent planning assumptions across plans […] aviation and rail access to the EU.

4.Remind departments of the need to consider the financial […] commercial firms that play a role in their contingency plans.