Operation Yellowhammer

Overview
Operation Yellowhammer is the codename used by the UK Treasury for cross-government civil contingency planning for the possibility of a no-deal Brexit. In the event of exit with no-deal, the UK's unilateral departure from the EU could disrupt, for an unknown duration, many aspects of the relationship between the UK and European Union, including financial transfers, movement of people, trade, customs and other regulations. Operation Yellowhammer is intended to mitigate, within the UK, the effects of this disruption, and would be expected to run for approximately three months. It has been developed by the Civil Contingencies Secretariat (CCS), a department of the Cabinet Office responsible for emergency planning.

In early August 2019, after Boris Johnson had become Prime Minister, the Cabinet Office "was not able to confirm" that the Operation Yellowhammer plan remained in place, although a Yellowhammer document from earlier that month was leaked in mid-August and continues to be updated.

On 3 September 2019, Chancellor of the Duchy of Lancaster Michael Gove, whose responsibilities include preparations for a no-deal Brexit, said in the House of Commons: "Operation Yellowhammer assumptions are not a prediction of what is likely to happen, they are not a best-case scenario or a list of probable outcomes, they are projections of what may happen in a worst-case scenario." An otherwise unchanged version of Yellowhammer leaked earlier to The Times was titled "base case" scenario rather than the "reasonable worst case" scenario of the officially published document; a copy given to the Scottish government was titled "base scenario".

The Sunday Times has reported that Yellowhammer is one of three scenarios being studied, with the other two being Kingfisher, involving a support package for distressed British businesses, and Black Swan, a disaster scenario. Michael Gove has characterised the report as inaccurate.

Planned activation
Operation Yellowhammer covers actions to be taken in a no-deal scenario, some of which would be implemented prior to the date of leaving. Consequently, full activation of Operation Yellowhammer was postponed until 8 April 2019.

Operation Yellowhammer's name and logo
The existence of the operation leaked on 6 September 2018, when a press photographer captured a snapshot of a document revealing some "no-deal" plans and the HM Treasury codename for them. The document appeared to indicate the CCS had been used in anticipation of government policy. No further details were revealed. The National Audit Office subsequently made public some documents about the operation.

The operation code name "Yellowhammer", which relates to a small songbird, was chosen at random according to The Times.

On 2 February 2019, The Times received leaked documents with this code name, about Department for Transport command and control structure plans.

The Sunday Times has reported that Yellowhammer is one of three scenarios being studied, with the other two being Kingfisher, involving a support package for distressed British businesses, and Black Swan, a disaster scenario. Michael Gove has characterised the report as inaccurate.

Some online leaks and rumours said the official logo would be either the songbird or a hammer tool on or of the Union Jack flag.

Dover and Calais
The mayors of Dover and Calais, along with the heads of their respective port authorities, said in mid 2019 that there would be no Brexit related problems in their port and cities after a no-deal Brexit if politicians stop interfering with the running of them or the customs and revenue agents that worked in them.

Ireland and N. Ireland
Just in time supply planning and repeated border crossings by some individuals each day would end up with a

Cost and resources used
In March 2019 the CCS had 56 people working internally on the programme; it is estimated 140 would be needed to maintain the operations centre and it has been budgeted to cost £1.1 million in 2018–2019. This is in the context of the UK Treasury allocating £1.5 billion for Brexit preparations by government departments in 2018–2019.

3,500 troops were placed on standby to 'assist the civil power' in the event of issues arising from a no-deal exit, although the Ministry of Defence had only disclosed their mission will be to "support government planning".

Criticism
On 21 March 2019, the UK government's decision to risk a no-deal Brexit and to invoke Operation Yellowhammer was criticised by the First Minister of Scotland, Nicola Sturgeon. Her sentiments were echoed by the First Minister of Wales, Mark Drakeford. The Brexit party called it all lies and many thought it was a chaotic and uninformative mess.

Release
It was leaked to the press in the August of 2019 and was reluctantly published in the September of that year.

Also see

 * 1) Brexit
 * 2) Meaningful vote
 * 3) Hard Irish border
 * 4) Irish border question
 * 5) 17/09/2019 UK alert
 * 6) 24/09/2019 UK alert
 * 7) No-deal Brexit scenario
 * 8) Just in time supply planning
 * 9) Eurosceptics and "Little Englanders"
 * 10) The European Research Group (The ERG)
 * 11) Jeremy Corbyn's January 16, 2019 vote of no confidence
 * 12) Operation Stack (Brexit, trucking) and Operation Broc (Brexit, trucking)