How was the £350 million per week Brexit NHS figure calculated and by whom?

1. How the number was calculated — the raw arithmetic

The figure traces back to official Treasury estimates of the UK’s gross contributions to the EU: Vote Leave used the annual totals published for 2014 (£18.8 billion) and 2015 (£17.8 billion) and converted them to a weekly number — roughly £340–£350 million a week — to produce the eye-catching slogan on the red campaign bus ^[1].

2. Who put it on the bus and who amplified it

Dominic Cummings, Vote Leave’s director, is widely credited with creating and promoting the slogan, while leading Vote Leave figures including Boris Johnson and Gisela Stuart reiterated it on air and in campaign events; the claim was emblazoned on the campaign bus and became the signature Leave pitch promising money “for our NHS” ^{[1] [4]}.

3. What that gross figure left out — the nitty‑gritty critics highlighted

Fact‑checking organisations and economists stressed the difference between gross and net payments: the UK receives a rebate and EU spending in the UK (for agriculture, regional funds, research, etc.) which reduce the net outflow; once these are accounted for, the UK’s net contribution was far lower — estimates put it closer to around £140–£234 million per week depending on what items were included — and many of those net savings would be offset by other commitments and economic effects of Brexit ^{[1] [2] [3] [5]}.

4. Why the figure could not simply be “redirected” to the NHS

Analysts and the Treasury’s watchdog pointed out two practical barriers to treating the gross contribution as an immediately available NHS pot: first, the UK still faced transitional and settlement payments to the EU (the so‑called “divorce bill”); second, leaving the EU carries macroeconomic consequences — lower growth or higher borrowing — that independent bodies like the IFS and OBR said would weaken public finances and more than offset any simplistic “dividend” ^{[3] [5]}.

5. Political fallout and competing claims after the referendum

After the vote, many Leave figures downplayed or revised the claim; critics called it a “misuse of official statistics” and some Leave politicians publicly conceded errors, while others, including later ministers, reclaimed or reinterpreted the rhetoric — for instance Boris Johnson at times defended or inflated the headline — and debates continued in court and in public inquiries about whether the wording was a deliberate deception or a political shorthand ^{[2] [6] [4] [7]}.

6. How experts judged its significance in retrospect

Independent commentators and health-policy analysts conclude the slogan’s political power mattered more than its technical accuracy: it shaped voter expectations about a Brexit “dividend” for the NHS even while subsequent public‑finance accounting and independent forecasts showed no clean net saving from EU membership that could have been ploughed straight into health spending ^{[8] [9] [5]}. The consensus among fact‑checkers and fiscal institutes was that the £350m figure was a headline‑friendly gross metric, not a realistic estimate of money the government could simply reallocate to the NHS without offsetting costs or commitments ^{[2] [3]}.

Limitations of reporting: official documents and campaign internal memos would provide fuller forensic detail on exactly who drafted the bus slogan and the internal decision‑making; the sources assembled here summarise public records, fact‑checks and post‑campaign commentary but do not reproduce primary campaign drafts or all Treasury working papers ^{[1] [4]}.