Child benefit withdrawal will make it better to work less for families with over seven children

And come 2076, that will be the case for every family in the nation.

The child tax credit withdrawal, taking effect on Monday, will lead to marginal tax rates of over 100 per cent on families with more than eight children earning between £50,000 and £60,000.

The IFS explains how the marginal rates are calculated:

Affected taxpayers will pay back one per cent of their family’s Child Benefit for every £100 by which taxable income exceeds £50,000. One per cent of Child Benefit is £10.56 per year for a 1-child family, and an additional £6.97 per child for larger families. Hence the marginal tax rate between £50,000 and £60,000 is increased by about 11 percentage points for the first child and by an additional 7 percentage points for each subsequent one. So, for example, while about 320,000 people will find that their marginal income tax rate increases to more than 50%, about 40,000 of them - those with three or more children - will find that it jumps to at least 65%.

They offer a chart with the rate calculated up to four children:

By seven children, the marginal rate rises to 99.35 per cent, and by eight, it breaks 100 per cent (106.32 per cent, to be exact). This means that any individual with a family of eight kids earning between £50,000 and £60,000 would be better off if they reduced their salary back down to £50,000. In fact, for that individual, they would have to earn £61,105 before their post-tax income was the same as it was at £50,000.

It's unclear whether any families actually exist matching that criterion - rather wonderfully, my back-of-the-envelope maths (which assumes that the exponential decrease in the number of families of each size continues: e.g., there are 1/8th the number of families with three or more kids as there are with two or more, so I'm assuming that there are correspondingly 1/8th the number of families with four or more as there are with three or more, and so on) suggests that there may be exactly one – but even if there are none at the moment, there's no reason why there won't be one in the future. Families with eight children do, after all, exist.

In fact, as time goes on, this problem will get worse. The IFS points out that child benefit is uprated with inflation, while tax bands aren't. Currently, each extra child after the first increases your "marginal tax rate" by around seven per cent, but suppose child benefit is uprated by two per cent a year. In that case, the marginal tax would exceed one hundred per cent for families with seven children next year; for six children in the year 2020; for five children in the year 2028; and, eventually, for families with just one child – i.e., every family – in the year 2076.

Hopefully the law will be changed before then, of course. But as a rule of thumb, laws which become ridiculously damaging unless you actively intervene ought not be signed in the first place. Oops.

Children. Photograph: Getty Images

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

Photo: Getty Images
Show Hide image

The Fire Brigades Union reaffiliates to Labour - what does it mean?

Any union rejoining Labour will be welcomed by most in the party - but the impact on the party's internal politics will be smaller than you think.

The Fire Brigades Union (FBU) has voted to reaffiliate to the Labour party, in what is seen as a boost to Jeremy Corbyn. What does it mean for Labour’s internal politics?

Firstly, technically, the FBU has never affliated before as they are notionally part of the civil service - however, following the firefighters' strike in 2004, they decisively broke with Labour.

The main impact will be felt on the floor of Labour party conference. Although the FBU’s membership – at around 38,000 – is too small to have a material effect on the outcome of votes themselves, it will change the tenor of the motions put before party conference.

The FBU’s leadership is not only to the left of most unions in the Trades Union Congress (TUC), it is more inclined to bring motions relating to foreign affairs than other unions with similar politics (it is more internationalist in focus than, say, the PCS, another union that may affiliate due to Corbyn’s leadership). Motions on Israel/Palestine, the nuclear deterrent, and other issues, will find more support from FBU delegates than it has from other affiliated trade unions.

In terms of the balance of power between the affiliated unions themselves, the FBU’s re-entry into Labour politics is unlikely to be much of a gamechanger. Trade union positions, elected by trade union delegates at conference, are unlikely to be moved leftwards by the reaffiliation of the FBU. Unite, the GMB, Unison and Usdaw are all large enough to all-but-guarantee themselves a seat around the NEC. Community, a small centrist union, has already lost its place on the NEC in favour of the bakers’ union, which is more aligned to Tom Watson than Jeremy Corbyn.

Matt Wrack, the FBU’s General Secretary, will be a genuine ally to Corbyn and John McDonnell. Len McCluskey and Dave Prentis were both bounced into endorsing Corbyn by their executives and did so less than wholeheartedly. Tim Roache, the newly-elected General Secretary of the GMB, has publicly supported Corbyn but is seen as a more moderate voice at the TUC. Only Dave Ward of the Communication Workers’ Union, who lent staff and resources to both Corbyn’s campaign team and to the parliamentary staff of Corbyn and McDonnell, is truly on side.

The impact of reaffiliation may be felt more keenly in local parties. The FBU’s membership looks small in real terms compared Unite and Unison have memberships of over a million, while the GMB and Usdaw are around the half-a-million mark, but is much more impressive when you consider that there are just 48,000 firefighters in Britain. This may make them more likely to participate in internal elections than other affiliated trade unionists, just 60,000 of whom voted in the Labour leadership election in 2015. However, it is worth noting that it is statistically unlikely most firefighters are Corbynites - those that are will mostly have already joined themselves. The affiliation, while a morale boost for many in the Labour party, is unlikely to prove as significant to the direction of the party as the outcome of Unison’s general secretary election or the struggle for power at the top of Unite in 2018. 

Stephen Bush is editor of the Staggers, the New Statesman’s political blog.