Why Sunak’s £2000 Labour tax attack line isn’t the new £350 million Brexit bus

Following an inaugural 2024 General Election TV debate hampered by the imposition of a 45 second answer limit, the debate about the relative merits of Rishi Sunak and Keir Starmer’s performances has been blown away by a £2000 tax bombshell.

The Conservatives had alighted on the threat of a £2000 tax hike for working families under a Labour Government as one of Sunak’s main attack lines. It was a line he repeated frequently throughout the debate, whether or not it was directly relevant to the question at hand – and at the time, it looked like it had landed well.

Keir Starmer took his time in rebutting Sunak’s tax line, and while he did challenge the basis of the calculations, many felt his response could have been clearer and more powerful.

Enter James Bowler, Permanent Secretary to the Treasury. On the morning after the debate, it transpired that Bowler had written to Shadow Treasury Minister Darren Jones MP, clearly stating that the Conservative Party’s line on Labour's tax plans shouldn't "be presented as having been produced by the civil service".

This contradicts Sunak’s claim during the debate that the £2000 figure was arrived at through independent civil service analysis.

For seasoned campaign watchers, this will not come as too much of a surprise. For some time, a mainstay of the Conservative election campaign playbook has been to calculate their own costings for various Labour policies so that they can use the figures as political attack lines. This process often involves an element of guesswork as to what the exact Labour policies and their delivery mechanisms might be – and given the circumstances, the political instinct is to assume that Labour pledges will be delivered at great expense.

However, the fact that Sunak repeatedly cited independent civil servants as the source of the figure, in contradiction of the Bowler letter which quickly came to light, has led to the £2000 tax attack line becoming the story of the debate – though not in the way the Conservatives will have hoped.

Why is this the case? Something that has come up frequently in conversation around the leadership TV debate is the widely discredited Leave campaign statement that Brexit would return £350m a week to the NHS. Despite regular debunking from policy wonks and ardent Remainers alike, it is widely felt that the Leave campaign’s use of the figure – including as a slogan on the side of a bus – was nonetheless an effective tactic.

It is too early to tell what, if any, the longer-term implications of the row over the £2000 figure will be. However, the short-term reaction following the release of Bowler’s letter has been broadly negative. What, then, could be different here to that £350 million on the side of a bus?

While a post-Brexit Britain was an unknown quantity, Sunak is trying to attack Labour on tax before a media landscape and audience of voters who are well aware that taxes have gone up over the past four years, and are on track to be the highest in more than 70 years as a proportion of national income. It is likely that you will attract more push back for criticising a hypothetical tax rise from your political opponent if your government has repeatedly raised taxes.

It could prove the case that the £2000 line is a blessing in disguise for Labour. Despite Starmer’s initial hesitance in pushing back live on air, the row over the evidence basis for the figure, and Sunak’s honesty in attributing it to the civil service, has become the story. More people saw the BBC news alert about Bowler’s letter to Darren Jones MP than watched the leaders debate.

All of this is currently providing Labour with quite an effective shield for fending off deeper questions about how it would carry out its spending plans in government without raising taxes beyond what the party has already announced. Writing in the FT today, Stephen Bush noted that the voting public do not seriously expect either party’s promises on tax to be kept. However, a protracted row about a discredited figure makes it easier for Labour to hold off on revealing its cards for a little longer. Looking at the polls, a little longer is likely all Labour needs