The Brexit saga in the United Kingdom is almost ready to enter its next phase. Instead of waiting until September to elect a new Conservative leader who would then become prime minister, Andrea Leadsom's decision to drop out has conceded the race to her rival, Theresa May. May's triumph has significant ramifications for Britain's future relationship with Europe and the U.K. economy, but she also struck a blow for transparency in election disclosures. May released four years' worth of her own tax returns, while Leadsom declined to release more than one.
Transparency about taxable income became an issue in the campaign because Leadsom refused to release any returns until she made the final ballot. May released her returns several days before Leadsom's announcement. She did so after Michael Gove, who was eliminated after the second ballot, released his own returns and called on his opponents to do the same.
In a strange twist, Leadsom dropped out of the race shortly after releasing her returns. She said that after surveying her fellow members, she didn't think she would have the confidence of enough MPs to form a stable government (the final ballot in the leadership race would have been a vote by 150,000 Conservative Party members, not just the parliamentary party). It is somewhat odd that she resisted releasing her returns for so long and then decided not to continue the campaign so quickly after she finally put out the single return.
Leadsom's returns were of interest because there was speculation that she had used offshore bank accounts when she ran a business with her husband. But her 2015 return didn't reveal anything particularly interesting. The MP earned about ₤84,000 and paid taxes of ₤22,000, for an effective rate of about 27 percent. During the same period, May earned over ₤112,000 and paid more than ₤40,000 in taxes. Interestingly, Leadsom's return showed no charitable donations, while May claimed only ₤685 of gifts to charity. U.S. presidential candidates would be ridiculed, if not outright attacked, if their returns showed such small gifts as a percentage of income. (There is some speculation that Donald Trump is refusing to release his returns partly because they will show a lack of charitable giving.)
The release of tax returns has become a major issue in many elections since Mitt Romney tried to resist releasing his returns in the 2012 presidential race. It is remarkable that Leadsom and Trump both decided to make an issue out of return disclosure after Romney's fate (and Trump seems to have made up his mind to allow this issue to be a part of the U.S. campaign until November). May didn't win the Conservative leadership contest because she released multiple years of returns and responded to Gove's challenge. But her action sets a precedent for the level of transparency that might be expected for future leadership candidates. In fact, it will be interesting to see what happens in the Labour Party leadership struggle, now that Jeremy Corbyn has a formal challenger.