Britain’s departure from the European Union has cost taxpayers more than £4 billion ($5.2 billion, 4.6 billion euros) in extra government costs, the National Audit Office said on Friday.
The government spending watchdog said departments will have spent at least £4.4 billion between the June 2016 referendum on EU membership and March 31 this year.
A total of £6.3 billion had been allocated for Brexit preparations, including for the possibility that Britain left the EU without a divorce deal.
Britain - an often reluctant member of the EU - became the first country to leave the bloc after nearly 50 years of membership on January 31.
It is currently in a transition phase until the end of the year and EU rules still apply, as London and Brussels try to agree a trade deal.
The NAO said the spending figures represented a ‘minimum estimated level of spend’ due to ‘limitations’ in the data provided by departments.
It includes £1.9 billion on staffing costs, £1.5 billion on building new systems and infrastructure, and £288 million on bringing in expertise and external advice.
Some 22,000 staff were working on Brexit preparations at its peak in October last year. They included 1,500 seconded from other government departments to prepare for a ‘no-deal’ exit.
London and Brussels reached agreement on the immediate separation issues ahead of Brexit, but a disorderly split remains on the table if they fail to strike a trade deal this year.
After the first round of negotiations this week, both sides noted the significant areas where they disagree.
The head of the NAO, Gareth Davies, said: ‘In preparing for EU exit, government departments planned for multiple potential outcomes, with shifting timetables and uncertainty.’
‘Producing this report has highlighted limitations in how government monitored spending on EU exit specifically, and cross-government programmes more generally.’
Alistair Carmichael, Brexit spokesman for the pro-EU opposition Liberal Democrats, said billions of pounds of taxpayers’ money had been ‘thrown away’ because of the ‘Brexit mess’.
‘The public have a right to know where it is all going. In the face of major floods and the coronavirus threat, we have to ask if the government knows its own spending priorities,’ he added.
Meg Hillier, an opposition Labour lawmaker who heads parliament’s Public Accounts Committee, accused the government of keeping the public ‘in the dark’ about its plans.
‘Data is limited, and the Treasury seem unconcerned by the lack of transparency,’ said Hillier, who voted against Brexit.
Want stories like this in your inbox?
Sign up to exclusive daily email
More Stories from Europe